I'd imagine these dreams were in the morning? Alcohol tends to suppress REM sleep thus once it's out of your system it causes REM-Rebound: your body's way of catching up on missed REM sleep; longer REM cycles more frequent once the booze is out of your system.

I've had this with drinking too but it's a double-edged sword for me. This (rarely) happens, more typically I just fall asleep and can't remember much in terms of dreams - but if I take a nap later that day or go back to sleep after waking up in the morning definitely get the REM Rebound.