Octomom -- Death Threats for Going on Welfare

Octomom's decision to go on welfare is pissing off people so much ... she's getting a flood of nasty messages and even death threats.

Hours after TMZ broke the story yesterday, our sources say Nadya Suleman started getting angry and threatening phone calls from blocked numbers, emails, and Facebook messages such as ... "Die bitch. I’m not working for your f**king kids, you’re the one that wanted them."

We're told Octo had to hang up on several irate callers, but not before they spewed choice words like:

-- "You're going to get yours."
-- "I'm not working to f**king pay --."
-- "F**k you, you don't deserve --."

According to our sources, Octomom's actually received a few positive messages too -- single mothers praising her for not letting pride stop her from doing what they believe is right for her children.

Despite the threats, we're told Octo has not called the cops ... yet.