Anxiety over a new baby

I'm just a few days away from the March 1st due date with our fourth child, and it's so hard to enjoy the thought of a baby in the house.
Everything else going on revolves around Calliope and her needs, then there are the 3.5 year old, and 1.5 year old that are also demanding.
Baby will be staying in our room. The little kids, Cooper and Clio, share a bedroom. Calliope has the larger bedroom, and it just isn't safe for a kid sister to share it with her.
We'll be in close quarters for some time until we are financially able to move into a larger home.
I'm not thinking clearly enough to write it seems.
Mostly I think I'm just wondering how much one mom can do.
I've got Calliope that could take up all my time.
I've got Cooper that could take up all my time.
I've got little Clio that could take up all my time.
Soon, I'll have a newborn that could take up all my time.
Somehow, I've got to take these four full-time jobs and do them all as one person.
I have my doubts.

Our plan is to labor and birth at home, and I just don't know. We got lucky last time with Calliope in school when the birth happened. I hope we get lucky again because I can't deal with her crap while I'm in labor. I won't have the patience or the ability to hold my tongue when she starts her bitching. When I'm not in labor, it's hard.