I have social phobia and I have a toddler. My SA doesn't get in the way of being a parent really. The problems are there regardless. I have a supporting partner and I can imagine it's difficult being on your own. I am glad I kept my baby because i've matured because of it and put me on the right path - I was really aimless, indecisive and self obsessed and am no longer that person.
That's just my experience though and I don't want to persuade you to go one way or another. Only you and your partner know whether you guys are ready. You might decide to not have it for now but when it comes to the time of termination or abortion, you might change your mind, it's known to have happened. You just have to go with what you feel.
This is a tough decision regardless of mental problems. Also keep in mind that if you do have a termination, it might reduce your change of having a pregnancy later on in life. I think you might want to write down pros and cons and look at it on paper to give you a clearer picture.