Why don't I want to learn anything?
This sounds like a classic case of burn-out. You've been working hard, maybe too hard, and it isn't fun anymore. I think a lot of academics do that at some point and you need to find a way past it to be successful. 

Some of the solutions can be fairly simple and others not. Getting advice from a counsellor or therapist may be needed. Probably useful in any case. 

Some people can just find a non-academic activity to spend time and effort on. I usually recommend something physical, but that will also engage your brain in a different way. My own go-to activity is Tai Chi, a mind-body fusion. In the past, I also used bicycling and skiing to get away from the academy. 

Such things can even be beneficial in solving academic problems, such as mathematics. When you get stuck on a problem, often letting it go for a bit will let your subconscious mind work on the problem and get you past the block. This too is a common experience. 

On a larger scale, a year away, doing things that aren't so academic or that use your mind in a different way can be helpful. Students who had the means, often spent a year "bumming around Europe" after graduation. A museum tour of the great cities. 

But if you just keep pressing and increasing the pressure, you probably won't improve. 

You might also want to look at some other answers here that discuss Imposter Syndrome (search for the phrase here to get some idea of what it is and how to deal with it.) I'm not reading clear signs in your question that you are "suffering" from that, but take a look.