"Real Housewives of Beverly Hills" star Russell Armstrong was at his wits end over his impending divorce from Taylor in the days leading to his death -- and he was inundated with debt.

Russell's lawyer Ronald Richards tells TMZ, Russell had been staying at a friend's house on Mulholland Drive in L.A. -- the same house where authorities found his body hanging last night.

Richards tells us, "I feel bad because his credit cards weren't working ... He had tremendous financial problems."

Richards adds, "He was also extremely bummed out about the divorce with Taylor. As far as a will, even if he does have a will, they don't have any assets, so I'm not sure what there would be left to leave. I am extremely saddened ... I had no idea he was depressed."

As we previously reported, Russell -- an investor who made his money in the 90s during the dot com boom -- filed for Chapter 7 bankruptcy in 2005, claiming he had less than $50,000 in assets ... and debt somewhere between $1 and $10 million.