I Recently Fainted And Ended Hitting My Head On The

I recently fainted and ended hitting my head on the ground pretty hard. At the er they said I had a closed head injury and syncope. I also bruised my ribs. They didn't know what caused me to faint other than I had an energy drink that night and a couple cocktails. Since then, which is almost a week ago, I've had diarrhea and also every time I urinate after sleeping all night my stomach starts to burn for no more then 5 minutes. I was wondering if this is common after fainting?