Is this normal??

My SO & I were having sex , & he asked to try anal .. he used lots of spit as lube since it was last minute & we didn't have any . Well it kinda hurt ALOT so I told him to stop & we just continued what we were doing before.. after we were finished I went to go pee & when I wiped there was some blood.. not alot but it kinda freaked me out.. it wasnt coming from my vagina , it was from my butt .. im kinda freaking out alot lol sooooo I dont know if this is normal or if I should go to the ER. Help????