You've got to consider in the first stages of a relationship, it's all butterflies and rainbows, everything's perfect and they have no problems so they will be shagging like rabbits.
Why not try and resolve the issue you with your boyfriend? Maybe it's your situation with your mum which is putting tension on your relationship? I think you should focus on that more than anything, especially as you've been together for over 2 years.
The only thing you can do is tell your mum how she's making you feel. You need to have a heart to heart and she may consider taking you back and resolving it and being more of a mother to you. If that doesn't work, then I think you should start saving to move out alone or you could possibly find your brother and ask to live with him?
Where I live, we have places for runaway children. You go there and you get a room and food etc. It's practically a kiddie version of your own apartment and they look like pretty nice rooms. They don't contact anyone or ask anything of you. So maybe you should look into some place like that. I'm sure they'd take you in considering your current situation because you inevitably have no where to stay.

I am sorry that this is going on in your life
what she is doing is wrong. very wrong. no mother should ever choose a boyfriend/girlfriend over their own children or family. my dad did that to me.. chose his new wife and 2 kids over me. i was heeart broken and it was very hard. eventually cas(childrens aid) got involved and took me away from home. I think you taking a break is a good thing but for now stop talking to her.. let her realize what she has done.. dont let her peer pressure making you give in....
stay with you boyfriend... atleast your safe with him... when your mom realizes what she has lost she will quickly snap back into reality. and whenever she does decide to try and get you back dont let her back into your life so easily.. because then she will think everything is ok. sit her down and have a serious convo with her and tell her everything
good luck

well then thats just plain selfishness then
wahtever then whats been done has been done
just forget about her. move on.. it will be hard because she is your parent but i wouldnt want a parent with an atitude like that..

yes this is a true statement but sometimes its best to let go of those we love
when all they do is reject us and make us feel worthless
in my case my dad made me feel worthless. he abandoned me for my step mother and my brother and sister... we talk now but im still warming up to him
I replaced him with my father in law for a bit.
I know how you are feeling and I know this isn't easy to hear but its probably the best thing for you to do at this point.

Do you have any relatives that you know other than your mom? They might be able to help you. Spend time with your friends, your best friends can always be there for you.

About your mom, just let her go. =/ If she has made a decision, sounds like there is nothing that can change her mind judging from the story about your brother that you told us. One day, she will regret it. If not, then why even care?

What do you do right now to get money for the tuitions? Money is important, make sure to manage it well assuming that you depend on your own right now. [NEVER consider to be a prosititude. Sorry if this sound offensive, but at this moment seems like everything could happen to you. I just wanted to remind you.]

Hope things get better somehow. Never give up! Life is a bitch sometimes, just consider it a challenge, yeah?