Is there something wrong with me?

Most days, I just feel shitty for no reason. I never really want to leave my house, but I do when my friends force me to go out because I don’t want them to think anything is wrong. When I’m out, things seem pretty fun, but there’s always this underlying feeling of anxiety or sadness. I feel like I’m moody and upset for no reason all the time. I can’t focus/ don’t really care about most things anymore, but I just force myself to go to class or hang out with people. I feel like a failure at everything right now: in school, where I used to be a 4.0 student, I’m struggling to get Bs and Cs, emotionally, I’m all over the place, physically, I’m gaining weight and always slow/drowsy, and socially I just feel like I can’t make friends/ don’t have the energy to interact with the ones I have most of the time. People would probably prefer to hang out with someone prettier and with a better personality anyway. I just feel pretty damn useless, and I don’t know what’s wrong or how to fix it. I just don’t want to have to do anything anymore.