AITAH for not leaving my apartment when my girlfriend wanted “girl time”

My girlfriend and I have been together 2.5 years. Living together for 6 months. Prior to moving in together, we had both been living alone for 5+ years. Neither of us had really lived with previous partners.
My girlfriend told me about a week ago she was having her bff over. Not a big deal- we have a second living space downstairs and I love my alone time down there.
Last weekend however, our downstairs flooded. It’s a mess. Cannot hang down there.
I had originally planned to go to the gym after work today. It’s also my first week returning to the office in a long time. However, forgot my gym bag at home this morning.
I get home today and do some chores- set up a dehumidifier our landlord dropped off, threw some laundry in, fed the pets etc.
Girlfriend comes home with her bff. I can see it already on her face she’s annoyed I’m even there. I say I am going downstairs to take care of some stuff. I have to take pics of things and make piles to get rid of for renters insurance. She says I should go to gym and I reply I don’t really feel like it. She’s obviously annoyed. Says something along the lines of “you knew bff was coming over and the plans.” I kind of snapped back “yes that was before our apartment flooded.”
She and bff ended up going out to dinner and i stayed home. Side note- bff also has husband at her place so i assume that’s why they didn’t go there. But also- didn’t kick him out?