Hi,
Do just be aware of the length of time it takes to go through the application and HR clearance process. Plus it sounds like you don't really know what you want to do going forward....
Your job might be stressful, but If you aren't earning and you have non-negotiable outgoings (rent/mortgage, food, student loan etc.) then that is an additional source of anxiety.
That said, we only have one go at life, and if you don't feel that your current career is what you want, then you should change. But i would look at your options from the security of your current employment, or at least make sure you have liquid savings equivalent to 3 months of your earnings to support yourself.
Hope this helps.
Al