Multiple sources with direct knowledge tell TMZ, Britney's mental health has been in a tailspin since the conservatorship ended. They say she often is not taking the meds that stabilize her, and she is drinking and using various drugs which is especially dangerous, because she has substance abuse problems that sent her to rehab multiple times.

We're told Britney has radical mood swings and often goes into rages that end in physical violence. There are times we're told it's impossible to communicate with her because she can't engage in rational conversation.

What's even more problematic ... we're told her current boyfriend, Paul Soliz, a felon, is running her household, and her life. TMZ broke the story, earlier this month Britney and Soliz got into a physical fight after a night of drinking at the Chateau Marmont hotel on the Sunset Strip where she ended up half-naked in the hallway, screaming at people. An ambulance was called after Britney hurt her ankle, and badly. They also got into a fight in a Vegas hotel room that caused so much damage, Britney paid the hotel thousands of dollars for repairs.

The sources with whom we have spoken all say ... it was a huge mistake to end the conservatorship, though they add her dad, Jamie Spears, was no longer the right person to run the show, mostly because she came to intensely dislike him.

It should be noted, after more than 2 years of post-conservatorship allegations against Jamie for various alleged financial misdeeds, Britney and her dad settled -- Britney did not get a cent from Jamie and ended up paying her lawyer millions in attorney's fees and she also paid Jamie's $2 million attorney's bill. In short, her legal fight was a bust, and people around her fear the legal bills and her wild spending are putting her on a path to going broke.

Our sources believe the point of no return for the conservatorship came when a story was reported that Britney's bedroom was secretly bugged, which people in the #FreeBritney movement felt was a gross invasion of privacy. After that, the cry to end the conservatorship was like a tidal wave ... so much so, the judge who ended it shockingly didn't even order a medical evaluation.

TMZ now knows what was behind the bedroom surveillance -- nothing, because it didn't happen. Five sources with direct knowledge tell TMZ, there was never bedroom surveillance.

These sources tell us ... it became apparent Britney was getting drugs from someone, and it was so alarming, people handling the conservatorship went to the judge, who signed an order authorizing the monitoring of Britney's communication devices to determine who was supplying her drugs. To be clear, the judge believed a drug dealer was fueling Britney's addiction, and authorized the surveillance.

Our sources have asked us to post this story, because they believe without people understanding the reason for the surveillance, there would be no way a judge would "have the balls" to withstand public pressure to create a new conservatorship.

Every source we've spoken with says ... if things continue the way they have been going, Britney is in grave danger.