Over 50 days late...

Been off Nuvaring for like 4 months, my periods were coming every month, but now it's been since the first week of July that I have had my last period. my husband and I have had unprotected sex last month and a half. I have taken hcg pregnancy tests and they been negative. But why the heck has it been over 50 days with no cycle? I do get cramps like I'm on my period, but I don't bleed! In so confused...