I need a bit of help, this morning I was tempted and nearly fell into mortal sin several times. Throughout the day I struggled with angry thoughts, and have been bombarded with angry memories. Today is really rough because, I don't have many opportunities to pray my chaplets and I have to spend my family and they really irritate me -especially my mother and my brother- because of their moral failings and, how they are often at odds with each other.
I am a bit better now, than I was earlier, but I still prayers that I can pull through today and not fall into sin. Also, I don't want to go into this but, I'm a bit worried about backsliding, I don't get into this, but please pray that I'm safe from that danger?
Anger is just an emotion. The Bible says "Be angry and sin not." So it is not a sin to be angry. It can, however, be a sin what we do with our anger. I take it that's what you mean be "almost falling into mortal sin." The temptation is to abuse others with our words by demeaning and insulting them, accusing them falsely, dumping everything they have ever done wrong on them, resorting to sarcasm, taking the Lord's name in vain, using profanity, yelling at them, threatening to harm them or ourselves, etc. In extreme cases, we can even attack property or lay hands on the other person. But on the other hand, it is actually a very healthy form of communication when we say, "I feel very angry when..." or "I'm very angry right now because..." and then give specifics.
Always remember that "This too shall pass."
Keep you mind on getting what you want, which is to resolve the problem, NOT to express your anger. If you stay focused like a lazer beam, you'll have nothing to regret later on, and you'll come away having accomplished something. Often, the anger continues for a while after the fight, because it takes two people to resolve an issue, and the other person may be unwilling. This too shall pass. Anger burns itself out, and you'll feel tired and better. In fact, having cooled off, you may have a new perspective and see some different solutions, and feel like going and trying again fresh.
Sometimes the other person may simply be toxic, and the best you can do is cut them out of your life, or if that is impossible, avoid them as much as possible, and be simply polite when you must see them.
Learning assertiveness skills is always a plus if its someone you love but seem to get into skirmishes with, such as a wife or child. It sounds like a lot of your difficulties fall into this area. Let me know if you want to discuss assertiveness.