could i have a cyst? or.....

I am officially a week late as of today with my period. I've been taking numerous tests and all but a couple came out negative .. the others were shadowy :/ I have most pregnancy symptoms but today and yesterday I have been cramping and pains on both sides were my ovaries are...I had this kind of pain n cramping with my other children.when I was pregnant but why am I getting negatives? Could it possibly be a cyst?