Is Cramping And Brown Discharge Side Effect Of Plan B?

Hi i am a mother of 10 month old babygirl. Ever since i had her i never got on any type of birth control. Me and my husband had sexual intercourse the first week of september and we always use the withdrawel method. Well we had a little scare so to make sure we bought the plan b pill. A week after i took it i started to get really bad cramps like if i was going to get my period and i started to have some brown discharge for like 2-3 days. I am very regular with my period and i was supposed to get it Sunday Sept. 26 but i didn't. But Monday Sept. 27 i started to get cramps again and i started to have some brown discharge. It's not enough to cover a pad but only when i wipe myself. Could it be a plan b side effect or could i be pregnant again?