Hugs, this age is hard (16 months was when our 18m sleep regression hit) and add to that teeth it's a recipe for awfulness. Congrats on your news, I know it makes it totally exhausting!
I think Zoe is spot on with her advice to shorten the day. I also think consistency is key at this age, so if it were me I would set naptime and bedtime, aiming for or at least allowing a 12h day for now (personally I found 13h days were always too long for DD, even on a good nap). Our routine at this age was WU 6.30/7, nap 12, BT 6/6.30pm - though I should say that 3x a week DD was in daycare and usually didn't nap more than an hour there which is probably why the shorter day worked for us.
Good luck!