Oh Holly, I read this and just wanted to come and give you a cuddle.
What you need at the moment is support. Preferably near to you in person, although I'm certain MN'ers will offer lots of comfort and advice here.
Do you have a close relative that you can turn to for unbiased advice and real emotional support for you?
If not, then do lean on your BF's parents a little, and talk to his Mum openly ( they will be your childs grandparents, so nothing wrong with getting close now ) - just do remember that they will have a bit of an agenda.
There are several things I would say, if my own daughters had been in this position ..........
firstly, what you do is totally your choice. Either option is a hard road, and only you know, in your heart, which one is the right course for you. Don't let anyone sway you from that course, because if it is not what you really want then you will live with it for the rest of your life.
Second, you have not ruined your life - it has just changed direction. Your mother may feel that her own was "ruined" by early motherhood, and her own experience, but that is not your story. It is now not going to be easy to achieve, and your mother may have kicked off because she recognises that and wanted "more" for her daughter. That doesn't make her response right, and it really does not mean that you don't still have a wonderful life ahead of you.
Thirdly, having a child does not mean that you cannot continue studying. I know 2 people who have continued their Open Uni degrees while pregnant/with newborns ...and both have done well. You just need to explore the OU option now, rather than waiting.
Next, I want to reassure you that you need not repeat parenting patterns. Young (and unexpected) parenthood doesn't make you an abusive mother. Not if you want to change the pattern and be a better parent. Trust me on this! ..... you can do a less abusive job of mothering 
Finally, you do not need to suffer continuing physical violence from your mother and it is not good for you. Consider the option of staying with your BF parents for a short time, if you need to get away or feel under any continuing threat. Do go to Citizens Advice and talk through what your options may be for housing etc etc
Sorry this is long, but verbal "hugs" take a while.
They will be of little use, but have some
....and a
now that you will be off the
!!