Tiff was out Wednesday in L.A. when a photog asked her what went wrong. In a nutshell ... she's been burning it at both ends. She said, "I've slept in my bed a grand total of 28 days" for all of 2018. She added she now knows exactly what happens when your brain is fried.

That being said ... she admits going hard on the party scene didn't help either. As Tiff put it, "Miami is a really dope city, and I probably shouldn't turn up before work."

She also found out who her real friends are, and ran down the all-star list of comedians who reached to show love and support.

As for the haters -- Tiffany has a message for them too.