I am so sorry you are here. It's a good place to be.
I got the 7 year itch as well and I am separated for 6 months now. Things are looking a bit better for us now but it started just like you described it "I am done, etc etc".
Do not get discouraged. You still have time. Read the instructions to newcomers and of Successful people that busted their divorces. All you need is in there. Use it wisely and CONSISTENTLY.