I know that feeling of frustration when you lose a game. There's always going to be a better player though. At least chess will teach you that quickly enough.
In your last game ...c5 isn't so good, because you end up with a weaker pawn structure after Bxf5. Doubled pawns can give you open files, but they can also be real weaknesses. Here after move 11 you see the problem. You were able to defend it, but by defending the pawn, you made the dark squares incredibly weak. A weak color complex is another weakness.
You might want to try out Silman's book 'Reassess your Chess'. I've always used it to train my pupils. You could use it to get to know what typical strategy could be. Focus on the static weaknesses. You don't have to go too deep. Just knowing and seeing what you could do about a bad bishop, and applying that in your own games, helps you out with middlegame strategy. The 'dynamic' advantages, like lead in development, are a bit too difficult for now, so I wouldn't worry about them yet.
Btw, in your last game, there were not a lot of things that you need to be too worried about. Notice how the game ended by losing a piece. This is why first and foremost it will always be most important to look for tactics and get better at tactics. When I grew up, people would say you could get to 2000+ with studying tactics only. That really shows how important it truly is.
I try to post my progress regularly how it is going. My goal is to achieve 1200 until the end of the year. I feel somehow this goal should not be too hard to get too, but since i was over 1000 i lost a lot of points due to tired playing and tilt. It frustrates me that im just too dumb in this moments. I thought im decent intelligent (no genius either!) but somehow it feels chess breaks my brain. I studied informatics and see myself as a somewhat analytical guy, but i can't get my head around it.
So if you wanna hear how it is going, and see me raging, feel free to come back