22/23 weeks and already uncomfortable

Flutatious1

So, I'll be 23 weeks on monday and I've been starting to feel some discomfort already.  Since I'm only 4'11", I have a feeling it's because I have less room than most people.   My back has starting hurting - both upper and lower and I can't get into a comfortable sitting position.  When I lean forward or sit upright, I feel like all my insides are being squished.   Need some advice......got any?