Someone help.

Is it possible to be pregnant and get you're period and cramps? I took 5 hpt and got all positive. I went to the doctor they did a urine test and it was negative and they said it could be because it's too soon because I would only be 4 weeks. Today would be the 5th day my period would have been late but I woke up to my period and terrible cramps. Is it possible I'm still pregnant?