9:24 AM PT -- Britney just moments ago posted this picture with her boyfriend, Sam Asghari. She captioned it, "I love this man." Sam did the same a couple of minutes later and captioned his post with superhero emojis. Can't deny it ... they look great together.

Britney Spears isn't about to just slink away and hide in the wake of news she's nowhere near ready to perform again.

Britney went out for a coffee run to Starbucks with her sons Thursday in L.A. and looked happy and upbeat ... smiling and even cracking up laughing at one point.

This comes on the heels of a somber evaluation of Spears' current status by her longtime manager, Larry Rudolph, who told us she should not be returning her to Vegas residency "... not in the near future and possibly never again."

Brit already clapped back at this notion -- at least that's what it seems like -- by sharing a home dance video in which she flaunts her choreography ... by busting out moves to some Michael Jackson music.

It's unclear if the vid was Britney in current form or a #tbt ... but the implication is Britney's not about to throw in the towel.

As we reported, she's going through some issues at home ever since being released from a mental health facility last month. The reality is ... she's not doing well at all. Doctors are having trouble figuring out what meds are the best fit for her, and her parents are at odds over her treatment and conservatorship.

Britney restated in court last week what she's periodically asked the judge ... to end the conservatorship. Up to this point, the judges in the case have found reason to continue it. The conservatorship has lasted more than 11 years.

Britney appears to be keeping her chin up ... but multiple sources with direct knowledge tell us things are far from well.