What Causes Spotting And Back Aches?

i was drunk and i cant remember what happened. im on the pill. but im getting tired and my lower back aches my stomach feels bloated and is growing slightly. i feel sick and im getting spotting. im craving fish and chocolate also my legs ache when i walk for more then 15 minuits.also i had my period for only 3 days instead of 6 and it was basically nothing could i be pregnant?