Russell Armstrong Asked For Xanax Before Death

Russell Armstrong begged a friend for anxiety drugs days before his death ... TMZ has learned.

Armstrong's longtime friend and confidante Russ McCullough -- who appeared on "The Real Housewives of Beverly Hills" last season -- tells us, he met Armstrong for dinner recently ... and things had reached a new low.

According to McCullough, Armstrong couldn't afford to pay for his meal -- and when the subject turned to his divorce, Armstrong said, "This is as bad as it gets."

Armstrong also said he was distraught over his negative portrayal on the show ... and feared he'd never recover from the ordeal -- so McCullough gave him a Xanax pill to take the edge off.

We're told Armstrong called McCullough 3 days before his death, asking for a "full bottle" of Xanax -- but McCullough suspected something was seriously wrong ... and refused out of fear Armstrong might abuse the pills.