To OP:
You are not the first, only, or last person to experience Burn Out. Usually happens to everyone, just depends on when.
Sometimes things just don’t seem that interesting or important anymore. It has nothing to do with intelligence or any many cases, health issues. You may just saw “the light” a little too early.
No body here can help you. The only person who can get you out of this rut is you. Re-evaluate your life plans and goals to see what you want. School may not be for everyone, if you have an alternative plan in mind.