She was likely drinking paxlovir and getting hydro/UV light therapy. Don't resent your coworker for seeking treatment even if it looks like "fun."

I bet her boss would really like to see all of these Instagram pictures.

Fuck your life OP. But I'm guessing there's some deeper reason for your colleague's behaviour, as I read about this kind of thing in USA (I'm guessing you are from there?) often. I think it's very bad company policy to drive people to these kind of actions. Very happy to live in a European country, where I have 25 paid holiday days each year and a couple of paid bank holidays as well to make a grand total of somewhere between 30 and 35 paid days off each year. And this is even the bare minimum that a company is legally required to give you. On top of that, no reason at all is required and a company is legally not allowed to deny your holiday request, unless there are very very very serious reasons to do so. But "your colleague is also off" is not a valid enough reason for denial.

Did the same thing, I mean .. 2 weeks paid

is it mandatory OT? i get where you're coming from but you're getting paid extra for your time and you're there by choice (under the assumption that nothing is "mandatory") because im sorry, if a job needs people because of call outs/etc... they can ask you, but you aren't required to do shit extra

report here to your boss

I was severely overworked during the covid restrictions, and making no money, so I admit I did the same thing. I made more money in my two weeks of relaxation than I did for the entire time of 'only essential workers working'.