Is this normal????

I’ve had my second laparoscopy for my endo in Dec 2017. Iud removed at the end of Feb 2018 and got my BFP on 4/18/18. I had bright red spotting that turned to brown on 4/17/18. Sore boobs and cramps associated. Implantation bleeding and cramping I’m assuming. But today is Day 4 of consistent bad cramping (no more spotting). Why am I still cramping? The pain has gotten up to at least a 6 and Tylenol isn’t cutting it. My doctor says to keep an eye and go to the ER if the pain gets too severe. Is this normal? Should I wait it out?