fiancée keeps asking if I'm pregnant TMI

For the past week now my fiancé has asked me twice now if I'm sure I'm not pregnant. I didn't say anything to make him think that. My period is about 4 days away according to glow. We are trying to conceive out rainbow baby. I asked him each time what makes him say that but he said he doesn't know why he said that. What do you girls think? Also my nipples are burning like no tomorrow. I went without a bra for the majority of the day and put a bra on later thinking maybe it was because I don't have a bra on but they are still burning. I feel as if they have more veins than normal. Please help