What should I do?

I found out today that I was pregnant. I want to be excited but I'm kind of nervous. The baby's father and I have been friends for over a year but we aren't together and he's now back in a relationship with his on again off again girlfriend (which I didn't know about beforehand). I haven't told him yet and I'm kinda scared about how he'll react. I know i don't want to be in a relationship with him, but I also don't want to raise a baby without its father. And that thought is impacting my decision. I've always wanted to be a mom but I'm not sure if I want it under these messy circumstances....