Missed 2 menstrual cycles. Last two dates were first week of april and may. Had physical contacts on 24 april and 28 may(unprotected) . Tested with 6 different brands of home pregnancy kits. Dates of test are 28 june ,3rd,5th,7th,15th,17thjuly (morining first urine samples). All 6 results were neagtive. Having abdominal cramps from last 3-4 days. Am i pregnant ? Or is there some other problem ? Please help.