It looks like you've come to the right place for support while you wait for your psych appointment. A wise man knows when he needs help and reaches out, so you're to be commended for being
open and honest. I'm sure that just knowing that others have experienced some of the same feelings as you is comforting. Your process of soul searching and looking back over your marriage is also a healthy exercise. Sometimes it's good to just pause and see where there might have been negative patterns or drifting in your relationship. A course correction is always better than abandoning ship, so hang in there.
If you're like a lot of us, you probably use the Internet to search on suspected diagnoses, whether it's a rash, bug bite, cancer, etc. Along with forums like this, there's endless organizations, resources, etc. to sort through. As you do your research, you might want to take a look at the book "Blue Genes." It's written by three doctors (Meier, Clements, Bertrand)who share their results from studying brain chemicals that affect our moods and personality. Maybe it will help you sort through things with your doctors and counselors. Anyway, I'll be praying that God leads you gently and clearly in the days ahead. I always liked the verse "...God is not a God of confusion, but of peace..." May that be your experience.