I just don't want to be a failure in my owns eyes and in everyone else's eyes I wanted to be talented and noticed for something important.
Medical laboratory technician is what I'm trying to get my certification in and the teachers said you have to be mentally okay for the career. I know I'm not mentally okay. I just thought I'd ignore it and just deal cause I need money and job security. I also need my degree not to be a waste.
I'm scared though because realistically I know that I am losing it. I feel like I'm on the verge of a serious meltdown and I don't want it to get worse where I seriously embarrass myself or mess something up badly and someone else suffers because I'm depressed. I'm really scared I can't handle anything.
First off, you
are talented and you are doing something important.

It easy for people to judge others when they don't share their experiences or problems. Ultimately, it's about being valued and valuing yourself and finding the healthiest ways of achieving that.
If you say you are "on the verge of a serious meltdown" because you feel that you are testing the limits of your ability to cope, it is probably worth while reducing the amount of stress in your life. This doesn't automatically mean changing your career path, but you can look at certain lifestyle changes that can reduce anxiety/depression and stress. Sometimes little improvements can make the difference (as well as helping your self esteem along the way). We aren't born anxious or depressed and (complex academic debates aside) it is something we can learn, so it follows we can learn our way out of it too.
I can recommend reducing the amount of time you watch Television or use the internet as these things tend to have effects even after they are turned off. Irrespective of what you are watching or doing on them, they tend to be habit forming and condition you in to a certain state of mind. In practice, it means giving up control of your emotions to other people, whether they be the producers or actors in your favourite show or people you interact with online.
Generally speaking, cutting out TV/Internet has one major benefit which is that you have more hours in the day. The average person watches 3-4 hours of TV a day, so you can use it to do other things. I have installed an app on my laptop which bans me from being able to access the internet, so I have been able to do things offline more. It's amazing how distracting and addictive it can be. I currently have a checklist on my wall for jobs I need to do once a week and a chart that tracks foods I'm eating which I probably shouldn't. It's small, but my room is fairly tidy and I've lost a couple of pounds. Still a long way to go, but any improvement is good. [note: checklists can be a double-edged sword if you tend to focus on little details so be kind to yourself. it is not a torture device and if it starts to feel that way it's worth reconsidering using them at all.

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If you drink lots of tea, or coffee or have a high caffeine intake, that could increase your anxiety too. It is addictive and the difference may be noticeable. If you have depression, don't touch alcohol as it will make it worse.
I'm stuck in a rural area and so I'm very isolated, but having regular trips out and visiting people for face-to-face interaction is a must. talking over the phone or texting is never quite the same and getting outside
away from all the stress at home maybe just to buy some new clothes or have a lunch can really break up the routine and get us out of the cycle of thoughts going round in our head. Simply going for a walk is a great idea (I have cats, but if you have a dog- taking it for a walk is a great excuse to get outside regularly).
Keeping a journal can help as a space to write out your thoughts, as can listening to music to change your mood either to relax or help you concentrate when your working on a project.
You could probably come up with more and these sorts of changes may seem daunting at first. There are options but they may not be obvious so you have to be willing to experiment and see what works for you. Not drinking and not having a TV felt strangely anti-social until I don't notice them anymore. Talk with your counsellor and get advice that will deal with your situation more specifically.
Feeling suicidal is an ugly experience and very difficult to share because you feel like your letting people down or hurting them by admitting you are that unhappy. Talking about it online can be helpful because you are anonymous and people don't take it so personally- they just see it as someone in distress and opening up to strangers online isn't so scary. Suicidal thoughts are usually an impulsive desire to "escape" situations and will pass (in my case maybe in a few hours after I go out or do something else which take me away from those thoughts). It may be triggered by specific ideas or experiences, so over time you may feel more confident to open up about it and explore
why they act as triggers (for me, its an acute sense of futility and powerlessness that nothing I do will actually change anything). A little bit of self-knowledge can be really helpful because it makes it easier to navigate the inner landscape of how you feel and gives you a bit more control.
There may come a point when you decide you want to take a different career path, but it is
your decision. Everyone else can go screw themselves because they don't know what you are going through. In truth, the people who would call you a "failure" are almost always insecure cowards maintaining a hollow conformist facade who are secretly disappointed with their lives and find the fact someone else is willing to take risks and make improvements for themselves intimidating. They hate life and they try to suck it out of people because they are so scared of living. We all make mistakes and we all made bad decisions- but that's part of the process of growing up. In 1000 years, we'll all be dead and no-one will remember us anyway and that can be depressing but it also means most of the things we think limit us aren't as solid as they first appear; they can be broken and there is no shame taking risks you think are worth while.
If your still feeling a bit worried, here's a picture of some kittens to help the process.