No period after starting and stopping pill

hi, ive been put on the mycrogen 30 pill (not sure how to spell it)and i took 2 of them after finishing my period and i then forgot to take them..so i decided id wait till my next period about 5 days after i had bleeding like a period..so i took another 2..and then realised it werent my period so stopped..on the 21st feb i had sex with my bf with a condom and it didnt split as far as i know.and then the day after i had realy light bleeding..sinse then i havnt had a period and im confused as to if or when i will.went to my clinic and she took a test and it was negative but she told me to take my pill for the full 3 weeks and then come bck for a test.but i keep getting stomach cramps like a period and no bleeding..and im really really worrying..i dunno if its all in my head or not but i cant tell my mum..and im waiting to go back to the clinic but im really scared. please help me. thanks x