I think it's sweet that the OP is so excited that she's going to have a baby soon. You can just tell the enthusiasm coming from her post!
However, as someone who has had two agonizing pregnancies, I can more than vouch for the fact that those spots (rare as they may be around here) can be lifesavers. And I'm sorry, but when you have no support system, and no one to pick up the slack, sometimes you do have to go out in public, even if you're in a LOT of pain. I remember going grocery shopping once because I had nothing in the house to eat - literally. DH was in the hospital and I hadn't felt good enough to shop for weeks and I was out of EVERYTHING. It took me about an hour to throw a couple of things in the cart, and I threw up (discreetly as I could) several times in the process. Every step was sheer willpower. People gave me dirty looks, but did anyone offer to help? On the other hand, what am I supposed to do, starve myself or my baby? Not every case is that extreme, I realize completely. However, especially if it's last minute and you're that pregnant and you have to get something before baby arrives. Or maybe you don't really NEED it but you're nesting and you might as well NEED it because it seems really that imperative.
I view those spaces as disabled parking, honestly, so I wouldn't take the spot normally. But in a totally empty parking lot early in the morning, that's not a big deal and I wouldn't bat an eye at it.
Congratulations, OP, on expecting.