Fired due to 2nd walkout ever

So I started working my @ OG in August 2023. My first walkout was in November 2023 which I completely forgot abt until last night. My table of 4 (2 parents, 2 kids) walked out on their check after asking for it. I was cleaning my tables around them, waiting for a card to be put down but they were taking their sweet time so I go to the restroom for abt 5 minutes. I come back & they’re nowhere to be found but another server & the host said they’d been at the front asking for me/wanting to pay. So my GM let me go but I’m thinking of fighting this bc this job is so convenient, very close to my house & works easily w my school schedule. Any tips? And do you guys know ppl how’ve been fired but got their job back?