I’m 33 weeks and 3 days . My stomach has been super hard all day it only hurts when i sit up or…

I’m 33 weeks and 3 days . My stomach has been super hard all day it only hurts when i sit up or start to walk . I can’t get out of bed with out throwing up. I tried to take a shower and started feeling light headed it’s my first pregnancy and i was wondering what i should do ?