Contractions or over reacting ?

Megan • 18| Mommy to Colt Michael due October 18’💙Taken By the CAT❤️

So the past couple weeks I have been having lower back pain and period like cramps but it was pretty tolerable it just worried me so I made an appointment with my doctor and he ended up being out of town so they gave me a new doctor until he gets back and the doctor did not care about anything I had to say and basically told me he wasn’t going to check for anything because I’m not one of his usual patients and he was “very busy”.... Well that was on Tuesday and it’s now Thursday and I’ve been having the urge to poop but I can’t, sharp tightening of the stomach, and radiating lower back pain. I just want to know if this is normal for first time pregnancy’s or if I should say screw it and head to the ER at the hospital. The pain gets bad but when it slows down I can fall asleep and feel okay until I wake back up , I’m almost 35 weeks and baby has been growing ahead ( idk of that helps narrow anything down)