Bad yoga poses?

Hi! I’ve been doing yoga for a while pre-baby, I’m actually a former dancer, so I consider myself pretty flexible. However, lately I’m struggling especially with the poses that stretch my front side like up-dog. I didn’t think it was bad to do that pose but does anyone know if the tenderness and stretching of the stomach is a bad thing or is it a normal feeling to feel so tight and inflexible there? 19 weeks tomorrow!