Having pain in my anus near the end when i sit down. no visual signs of a hemorrhoid. no bleeding. caused me to pass out from the pain resulting in a trip to the er but no relief since saturday. what could this be?

An abscess comes first to mind, follow up will be needed with your doc or a gastroenterologist, usually in discharge notes from ER.

Anal fissure, abscess or anal fistula, proctitis or inflammation of the rectum, or ano-rectal tumors, benign or malignant as well as hemorrhoids(external usually) can all cause pain and bleeding, to name a few. Get checked by an expert, either colo-rectal or GI doctor to get the corret diagnosis and appropriate treatment.