Hey Struggling Teen,
Sounds really hard. In terms of feeling proud of yourself - it's okay if you're not up to that point yet - you will get there bez"H. Instead of writing a list of things you're proud of, you can make a list of things you did that were good - regardless of how you feel about yourself or the deed. The Torah defines what's good/bad and whether you feel proud or not at this point, making the list will hopefully help you get to a point where you start to feel that pride. It takes time - it does NOT happen overnight - but it is very worth it.
The yetzer hora's most sinister tactics are to lead a person astray and then condemn her for it. Like, he'll distract a person from paying attention during davening, try to get her to think about what she's having for breakfast, her homework, the weather, etc. As soon as she finishes Aleinu, the yetzer hora changes tactics - he dresses up as a disapproving Rosh Yeshiva, telling the person how shvach her davening was, how terrible she is, how Hashem is disgusted by her tefillos. This disparagement then pushes the person's self-image down; she doesn't even want to try again, b/c the yetzer hora has convinced her that she is hopeless and worthless.
This is total sheker. The whole purpose of our existence is to try again and again to do ratzon Hashem. We fall and we get up. The yetzer hora wants us to fall and stay down. His biggest victory is to chain us to a wrong self-image and convince us that we are inherently bad with no hope of growth or change. This is wrong. It is false. It is damaging. The trick is therefore to recognize whose "voice" you're hearing - your own self, your neshoma, the part of you that knows, deep down, that you have worth and that there is hope - or the voice of the yetzer hora. In your case, I would strongly suggest - ignore the louder voice - that's the bad guy. Let your own voice come through. Do things you know are right, even if your yetzer hora tells you you're hopeless or whatever. Those actions will affect your mind, gradually. Don't try to fight the thoughts - notice them and continue doing positive actions. Write about those actions and review your list once a week. Say the self-affirming statements (see my previous post) out loud.
R' Avigdor Miller zt"l often writes about the importance of "being fake." In other words, "fake it til you make it." Put on an act - an act of goodness, kindness, calmness, whatever, even if you don't feel that it's really "you." The more you act in that way, the stronger the effect on your pnimiyus. Soon, he advises, you'll trick yourself into thinking that you are that good/kind/calm/whatever person. And that is who you will genuinely become. Don't look for instant results - these things take time.
Also, know that setbacks are normal and inevitable. Just use them as stepping stones to bounce back. Life is full of ups and downs - let me repeat that, ups and downs. The downs are part of the picture, unpleasant as they are. Falling, having a setback, making a mistake is a given. We're humans, not malachim. We are not expected to be perfect, only to do our best. Your best is just that - your best, at this point in your life. Not someone else's best. Yours!
A teacher of mine addressed the tactics of the yetzer hora in a shiur on davening. She said the following: regardless of how a person davens, s/he should finish the tefillah and say, "Another nitzachon (victory) over the yetzer hora!" This applies to anything - not getting angry, avoiding loshon hora, wearing a tzniusdik outfit when you'd rather wear something less so, paying attention to half a brocha in shemoneh esrei, smiling when you don't feel like it, taking 2 more seconds to focus on the brocha mezonos, etc. No matter how much you "could have done it better" or "how far you are from your goal" or "how much better Shprintze did it" - tell yourself, out loud, "Another nitzachon over the yetzer hora!"
Another thing, and the most important, is daven. Daven with all the desperation in your heart. Don't give up. EVER. Hashem sees your matzav - He put you in it! - and He is the One who can take you out of it and bring you to a healthier place.
Keep up your great work. You can do this! I give you a brocha that you should see the progress you make in each of its increments and feel pride - in yourself as a tzelem Elokim, as a Yid, as a human being striving to grow and change.