Battling to make a right decision.

Hey ladies I could sure use some woman support and advice. I am in a relationship with my sons dad who we had just 11 months ago and we have been through so much.. Now to the point we no longer live together but we have reconciled finally after so much hurt and heartache and we are now trying to work out our relationship.. Things are better than before but not the best.. We got into our relationship pretty quickly and within 5 months planned to have a baby. We have now only been together 2 years. My whole reason of this post is because I just found out yesterday I am pregnant again and I am so nervous to tell anyone in my family yet alone if I should even have this baby. We did not plan this one and we must have been being a little reckless. My sons dad is very upset about it.. We don't feel ready because it feels like we barely just had our son which is true. My sons dad is stressed and confused because he doesn't think abortion is the right thing to do but at the same he doesn't want another baby.. We aren't even living together together and are barely fixing our relationship.. Should I get an abortion since there's so much uncertainty and not stability in our households as being together as a family? I don't know what to do because I love him and I love our son and its hard to kill something so precious that is a blessing.. Some women have so much trouble having a baby and I feel foolish to kill something that is a blessing.. But I don't want my sons dad to resent me in the end or I don't want to be alone raising both babies if my relationship doesn't work out because of all the stress. Please give advice if you have any.. Also this will be my 3rd child if I have it.. I also have an 11 year old daughter I had as a teen so I just don't know if I can handle having 3 kids but I feel like it happened for a reason.. I don't know what the right thing is..