Supposed to have started my period two days ago

have yet to start, but cramping here and there. I got off my birth control a little over a month ago and bled for 6 days. Yet I was supposed to start two days ago, but all I've got was slight cramps. a few weeks ago I was in the e.r. from pain in my uterus, they took urine and blood, but the tests came back negative for pregnancy. They told me it could be a cyst on my ovaries. my boyfriend and I are ttc, I'm just worried.