Wow. Poor you. It sounds like the first abortion has already weighed heavily on your shoulders. You sound a bit resentful and I do not blame you.
I don't think you sound like you would be able to shrug off another abortion. Could your boyfriend expect you to have two abortions that you didn't want, and yet be exactly the same carefree happy girl???
You sound like an intelligent woman and you are young enough to build an excellent life for yourself and for your baby. But you are not so young that anybody would think it foolish to have a baby.
I understand that you're midway through your education, but you can continue to study until after the baby is born?
What about your parents and your friends? Would you have their support?
It's your life and only you know if you can fit a baby into it, but as much as you may love this guy, it sounds like he's not worthy of your love. A better man would have listened to you before now. It's sounds like your voice is the one that's not being heard in the relationship. How long could you, as an intelligent person, tolerate that? Revolving your life around his wants and desires, always! He, not even aware of the extent of your sacrafices. (I could be wrong).
If you tell him about this pregnancy and he lets you down a second time, ie, BLAMES you, tries to dictate what you should do without discussing it, dismissing your feelings entirely, only valuing his own wishes on this matter, then, I think you should take the baby out of the equation for a minute and think about whether or not to have HIM in your life.
I'm a single mother, and I'm 37 and tbh, it isn't the hardest thing in the world. Being with an uncompromising man who didn't realise how selfish he was, that was hard. I can tell you that firsthand. In a perfect World, I'd have had my first child a bit before I was 30. I want to be around for as long as possible and see as much of their lives as possible! So, imo, mid 20s is not crazily young to have a child. FAR from it.
I'm not anti-abortion, far from it, I'm a 100% choice. But reading your post I wonder if you could have a second abortion and then procede to 1) make your relationship work & 2) carry on with[out] him, without getting depressed.
I know this is a parenting site, so we are mostly mothers or want to be mothers here, but I have in the past advised people to have a termination and not to eat themselves up with guilt! Everybody has to do what will sit most comfortably with them for their own future.
good luck with a tough decision
xx