I think it's the anxiety that needs treating rather than the pregnancy, imo. It sounds as though your mum is quite supportive, but if you have told her you have some doubts, she is trying to protect you. My mum would do the same I think. If you told her you were keeping the baby, she would come round to the idea. My mum said similar things to me each time I was pregnant (I have 4) and loves them to bits anyway.
I am not anti-abortion, but in your case, I'm not convinced that's what you really want. Try telling everyone, whose opinions matter to you, that you are definitely going ahead with it. They will be more likely to give you support then, instead of options. This doesn't commit you to anything, but will give you a chance to really think things through yourself.