Pelvic pressure/pain

LP
The last 2 days or so I have had pelvic pressure/ pain. Not cramping. This morning it crept up out of nowhere and for about 5 minutes I was keeled over in pain. Heating pad and rest allowed it to dull back down again. 
I'm on cycle day 34, 16 DPO (my period was projected dec 5th) I've taken a test this morning FR rapid result and got nothing. I'm waiting for my doctor to call back but what do you ladies think? Anyone else have similar situation before?