Every girl is different when it comes to belly size, baby size, symptoms, and pregnancy in general so don't be worried. I knew a girl who barely showed even at 9 months. Wish it was me. I'm 36w4d and I'm huge and miserable. Not always a bad thing to be small lol.
Probably not. Your baby may just be in tour back. If your doctor isn't worried, don't stress yourself out. I would love to look like I was 3 months right about now. :-)