Is this normal?

I came on my period two weeks early for 2 days then came off again suddenly. two weeks later i had unprotected sex with my boyfriend. three weeks later i came back on my period quite heavy but for just three days? ive had no sickness except three days feeling as though i was going to be sick but never was. would you say this is norrmal i know i may sound stupid but ive never had to worry about my periods before there always on time.