Suppoze122yDon't worry. If you like your current team as friends I think there's a good chance you'll keep in touch later.
I also had experience with horrible management, causing overtimes, burnout and stress. But this very bad experience is what brought us together. And now, after quitting 2 years ago, all of us are on our seperate ways - but we still get together regularly and laugh about these unpleasant times.
If it were me, I'd certainly start actively looking, but I wouldn't hand my notice in until I'd found somewhere else. You want to be out of there ASAP, but no point in leaving yourself short in the meantime.
I'd contact your integrity officer if the company is large enough to have one.