I would like to offer two final suggestions for you to consider.
1.) Is it possible to take a leave of absence for a short period giving you the opportunity to "cool off" a bit and possibly get some clarity on your decision. Maybe you would feel differently in a month and more focused and refreshed. If not a LOA, then maybe a discussion with your chief pilot. Since you would be leaving anyway, there would be no harm in talking with him. Maybe you could do some duty in the training department. The new written exam rules that go into effect in 2 weeks require instructors with ATP's and 2 years of airline experience.
2.) Could you be happier with a different kind of professional flying? You mentioned flight instructing just now so that leads me to believe you might be open to it. What about getting on corporate or with a fractional? Would be best to do something like this while still current.