I have been there! My first daughter was 14 months when I became pregnant with my second, and it was a challenge. Down the road when I was pregnant with our third child, my older two were ages 2 and 4.
Nap when your toddler naps. Even if this means living with a messier house, the extra rest is worth it!
Consider activities you can do with your toddler that don't require much energy. Take this time to read stories, color together on the couch, or do a puzzle while you both lounge on your bed.
I actually just published a hub that relates to this topic - here is the link if you're interested!