Wow yours is a bizarre story. I can't imagine why your mom would turn on you like that. If you think that the breakup with your b/f was a factor could it be that she was somehow attached to him & now resents you for breaking up with him?
Maybe she had a vision of him becomming the perfect son-in-law, or something.
As for your mom "making you feel worthless" she can't do that unless you give her the power to do that to you.
From your information, I would describe you as a very responsible young woman. A person that any parent would be proud to call their child.
As a parent myself, I can't even fathom the concept of not supporting my child getting an education, & improving her lot in life.
It almost sounds to me that your mom may be suffering a mental or emotional breakdown of some kind.
I recommend that you get her to her family doctor, & you go with her, & explain her personality changes to the doctor.
The point is that whatever she is doing, this has nothing to do with YOU. I can't help but feel that you haven't painted the full picture here. That may even be unintentional on your part, you may be in a sort of denial, but you need to ask yourself a really hard question, & that is: IS YOUR MOM DRINKING?
That could explain A LOT.
I am going to leave you with one final thought. This hinges around you comming to the realization that this isn't your fault or your responsibility.
Even your mom would ultimately agree with me that your 1st responsibility is to yourself. If she persists in this behaviour, & refuses treatment for her condition (whatever it is) then you have to get out of that situation. You can't concentrate on your future if you are living with a person who is acting like a lunatic.
There are assistance programmes, & grants for students in bad situations like you are in. All you have to do is seek them out. Go to a councellor at your school & see if they can hook you up with some assistance. You didn't say where your Dad is in all of this, but if he's still around then consider him another resource to turn to.
Go ahead, & turn to as many people you can think of for help. You will be amazed at how many will step up & offer you anything they can. Why? Because YOU ARE WORTH IT!
Hope I helped! ;-)