Positive then negative but still got symptoms.. please help


Please help, I got three faint positive tests through out the week after being constantly nauseous and exhausted. I should be around 5 weeks but I took another couple of tests on Saturday and they were negative. However I’m still really nauseous, period is late, been having a sharp pain constantly around Belly Button and a sharp pain in the left side of my pelvis.

I haven’t stopped crying because I thought I was finally pregnant but I have no clue what is going on.. thoughts anyone??