Severe back pain ??

Ch
I'm 9w2d pregnant .....For the past 2 1/2 weeks I job been having extremely bad back pain. Especially while I'm trying to sleep. I sleep with a bunch of pillows. Have a body pillow as well. I try stretching but the pain still continues. If I go to the ER, would it be a waste of time or could they help me?? I been taking Tylenol but only one throughout the day.