This is weird but I'm getting worried?

I have strange sharp pains the lower of my stomach on the right side feels liken sharp pain sometimes it hurts both side it hurts to stand or walk. I had my period the 27 and off the 28. Had a pregnancy test a urine one came negative they took blood from me. I felt nausea the past week. Last Saturday woke up with swollen feet. What could be wrong with me???