B Belly sooooo sore!!

The bottom part to my B belly is so sore no matter what I do! If I sit too long, stand, walk lay down anything! Ugh. It hurts so much >_< 34 weeks here I've only gained 13 lbs this whole pregnancy and I also don't have a very big bump if anything no one can tell I'm pregnant so I have no idea why I'm so sore, feels like there's no support for my belly :(