My sleep study said that i only went into rem once, at the end. does this sound like a specific disorder?

Likely normal: Likely completely normal . Most REM sleep occurs toward the latter half of the night. Given that you are in a strange environment with a lot of hookups, most people don't sleep as well as they would if they were at home. Wait for the final interpretation, as the sleep doctor will address any concerns from the study that he/she feels is worth mentioning.