TLF ~ Don't feel bad about your questions. The good thing is you're ASKING them, so it seems so obvious that you earnestly desire the truth, and that's awesome
In my opinion, and I am aware that this is debateable - You CAN lose your salvation if you turn your back on God and continue to deliberately, willingly, and knowingly sin, and not repent.. pretty much just turning your back on God. We are not perfect; God knows that

But also if you're messing up, and you are TRYING to do better, God looks at your heart. Praise Him that you have conviction for that is a blessing right there!
As far as thinking about doing something b/c it is what God likes, there is nothing wrong with that. We are supposed to do things that are pleasing to God. Personally, there are times when I'd rather do my own thing, but I remember that will not please God, so I do what makes Him happy, rather than what makes ME happy.
As far as the whole faith and works (deeds) issue, they go hand in hand. Faith is what saves you. But the works come into play eventually, for you can't serve God without DOING things for Him, you get what I'm saying ?
If what I said is confusing, forgive me...

It is not even 9am, and I am in English class, passing time..
