A., you can do this. It will be an adjustment, but you'll find a way to manage everything on your plate. God doesn't give us more than we can handle.
I'm speaking somewhat from experience. My situation isn't exactly the same, but I was a single mom for 3 years. I had 2 small children, a full-time job, and zero help (financially or otherwise) from my ex-husband.
You seem like a pretty independent person, but I encourage you to ask for help when you need it. Will someone be staying with you after the baby is born? You'll be tired and overwhelmed, and it will really help to have someone around.
Even beyond the initial adjustment, you're going to need a good support system. I've never been good at asking for help, but I remember calling my mom one time, and bursting into tears when I heard her voice. I told her I was just having one of those days, and she was at my door within 15 minutes. Do you have someone like that?
It will also help to be conscious of the blessings in your life. You have the means to attend school; you're employed when so many people are not; you're presumably healthy; and you've been blessed with a child. I know I'm stating the obvious, but it's so easy to get overwhelmed and lose perspective.
I truly wish you all the best.