I agree - could be the paci is becoming a prop.
I know six months seems an age away but honestly, you will look back and this time will have flown. It's really important to consider yourself in all of this - you'll drive yourself mad if you spend all day every day inside worrying about naps (believe me - been there, done that, and it wasn't worth it!). Make a conscious decision to go out some days and let LO nap when and where they can. I found if I made it my 'plan' that it was going to be a rubbish nap day, but I was going to enjoy myself anyway, I always felt better than if I stayed in and naps were rubbish.
Did you have a think about the idea of discomfort or reflux?