back pain like whoa... :/

Ive been in pain for the past few days... and Ive had horrible pressure in my pelvis and it makes me stop what im doing... and sometimes i cant even sit. ive been getting up every three hours now im 34 weeks and at 31 weeks i was in the labor and delivery for three days they were trying to stop my contractions... they tried the magnesium phosphate and it didn't stop then and they gave me at least 4 shots in my arm and tried the oral medicine too... i was miserable... and i couldn't sleep. well its happening again. but idk what to do i have three kids at home and my husband works so i don't want to go in if i don't have to... but Ive tried laying down and relaxing and all that and nothing works :/