Any ideas?

Okay everyone... so I am now 10 days late for my period. I’m usually very regular with the timing of my periods every month. For the last week and a half to 2 weeks, I’ve had very strong cramping. Boobs hurt,nausea, bloating, back pain, and I NEVER wanna eat.. literally nothing sounds good. I’ve taken two pregnancy tests and both came out negative. My boyfriend and I weren’t necessarily trying for a baby but we’re preventing it either. So, what else could this be symptoms of?? Any ideas?