Side effects of birth control, pregnancy, or something more serious?

Patient: I’m on a Seasonique off-brand birth control, so my periods are every three months. I’ve been taking it for six months now with minimal side effects. However, this last period was different than any I’ve ever had. I was supposed to start my blue pills on a Sunday, but I started cramping (an unusual symptom for me) the Thursday before. My period started the next day (Friday) and only lasted until Tuesday. It was so much different than my normal periods always have been. Instead of my usual brief, very heavy bright red flow, I had only dark, almost brown sporadic spotting. My cramps were constant. One night, I had a specific sharp pain on my lower right side that went through to my back. I couldn’t move for the pain. I’d planned to go to the hospital if it lasted the rest of the night, but I managed to fall asleep and it was gone in the morning. Despite being finished with any sort of flow on Tuesday, I am still cramping constantly on Sunday. I’ve been feeling nauseous and vomitted once (very rare for me) about the same time every day, so I thought these could be some sort of pregnancy symptoms. I took a test that was negative on Friday.My main questions are whether this is something that could be a serious problem or if it’s just side effects of getting used to birth control and whether or not it could be pregnancy despite the negative test…Any help would be so appreciated.Thanks,Jordan

Symptoms: Constant cramping, nausea the same time every day, spotty period, possible pregnancy, 6 months into birth control.