Suggest Medication For Delay In Periods,cramps,fatigue And Sleeplessness

Hi.. I am 23 yrs old. I had sex on the 4th day of my periods, then to be sure. i took an i pill about 48 hrs later. After about 10 days of having the pill, i got a light period again, and from that date,its been over a month now that I have not got any periods. Also, I am having tender nipples, extreme mood swings, light abdominal cramps, sleepiness, fatigue, anusea etc. I tested with a home pregnancy kit, and it has come negative. Can I be pregnant?