Disappearing belly??

Nicole

So I'm on my first baby and I'm pretty big for 18 weeks. Definitely noticeably pregnant! So I woke up this morning and my belly is just completely gone! Did he just move backwards or something? Does this happen to other people? It was just really odd shock and confusion when I walk past the mirror! I just listened to his heart on the Doppler so I'm sure everything's okay, but it was just really freaky! Does anybody know why this would happen? First picture I am 18 weeks, second picture I am 19 weeks!