Sorry Novels, I'm on the fraudSeer pathway so my expertise isn't very deep. If you had them opened recently maybe you can find something in history?
If you have a firefox profile then check it.
Maybe there's a backup or recovery file stored somewhere on your device?
So, to avoid repeating mistakes, I recommend installing an extension that keeps tabs on your tabs (hehe). There are a lot of them, and I’m currently using Tab Session Manager.
My condolences for the lost tabs though.