I Was Having A Prob Of Exess Bleeding During Periods

i was having a prob of exess bleeding during periods with swelling & severe pain in abdomain. i was prescribed with sevista 60 mg twice in a week, taken orally (13 tab) as per the prescription, now after one period, the period is stopped. Dr. says it is due to the med, now period may start again or may not..................i m still 40yrs, worried............. how i can be sured about the pregnancy......or what i should do now....