Excited about getting pregnant but also SCARED OUT OF MY MIND!!!

I'm 29yrs old, and as you can see by the subject line, I'm both excited and scared out of my mind about pregnancy. My boyfriend and I have been together for 7.5 years, and have recently made the decision that it's time for children to make an appearance in our lives. Since coming to this mutual agreement, I haven't been able to think about anything else. The day we discussed starting a family involved coming up with names...and how we're going to rearrange our apartment. I've been so excited about it, that I've told all of my family that we're going to be trying in the near future. But as I continue to talk about it, I'm getting more and more scared about the prospect of having a little baby in my life. Can we afford it? How are we going to pay off our debts if we have a baby to care for? Will we have to get rid of our pets? Can we afford a more reliable vehicle? My boyfriend is currently unemployed...and when he is employed he has only been able to get contract work that lasts a few months to a year at a time. Can we raise a kid in that lack of stability? Also, when I was growing up, I was physically, verbally, and emotionally abused by my step father, and I worry that I'll do the same to my kids. I also have IBS (irritable bowel syndrome) and take Immodium, daily. Is that going to have an affect on my child?
I've been told many times that I'll be a good mom, but I just don't know how to get over this anxiety. I know that there are many people who are in situations similar, better, or worse than me that are just as scared, if not more so. I just want to feel that my decision to have a child is a good one...and that I'll get through it.
My boyfriend, who is 32yrs old, is just as scared about having a child, but he has been extremely supportive, as well. If I didn't have him, I'd be more of a wreck...lol.