Hi I'm 22 And I Have Always Had Regular Periods.

Hi I'm 22 and I have always had regular periods. I was supposed to start my period may 7th, when i didn't I took 6 urine pregnancy tests as well as a blood test which all came back negative. I have had brown discharge and mild cramping for about two weeks. I am starting to have more red bloody discharge, lower back pain, nausea and cramping but still no period. I don't have a regular doctor nor insurance so I don't know where to go. Also I had a baby 5 months ago and have had regular periods since delivery.