Cramping severely but no period?

Olivia

The past few days I have been cramping. Just now, I started cramping so bad I was almost in tears. I never cramp so this is rare for me. But I am not getting my period? Is this normal? Me and my husband have been trying for a baby so I was hoping to be pregnant, but I tested the other day and it said negative and with all this going on, I would assume this isn’t part of pregnancy. So what could it be?