Well,I know how you feel. You dont want to burden your mother so you pretend all is fine.
I will tell you a little story before i go to sleep. I have a brother younger than I. My mother wanted him to go to an Ivy school. So he was extremely lucky to be accepted at Columbia University.
We packed him off and my mother (my dad had passed away suddenly) and i and my husband moved him into Columbia University- set up his room, bla bla bla....

He was there for 2 years...so we thought....(we lived in Massachusetts) He came home for Summer vacations, we would pick him up, move him back, the next year, same thing.

I had left all contact information for my brother at the Deans office, my mother paid out thousands of dollars, and i helped foot the bill too.

During his second year, i happened to call the schools office for something, i cant even remember now, and much to my dismay, i was told my brother was not attending school.
Had not been there all year.

I panicked and got so bad when my husband came home he found me crying and screaming. I could not tell my mother after she had sacrificed so much. To make a long story short, my husband had to tell my mother and you'd think a nuke had gone off- crying screaming, disappointment, wondering why, why, why...

It turns out my brother was having a terrible bout with depression and never left his room. The shock to my mother was horrendous.

I guess i'm trying to tell you that a young person is bound to have episodes like this, and hiding your feelings is worse than coming out flat and telling your mother exactly how you feel. She will be disappointed but she will be understanding. Tell her how you feel ASAP. I've learned its always better to come out with your true feelings, than to pretend, because in the long run, you will inflict more pain on yourself and your loved ones.

I hope my little story helped a little. God bless you and do the right thing.

You sound like a person i'd be happy to call my son/daughter.