I left after 23 years, and not a moment to soon. I enjoyed most of the time I spent in, not all of it. But, I'm glad I joined.
I left, and never looked back. If I'm honest, I don't actually enjoy flying anymore either.
The RAF (Fast Jets), is for young men and you will know when it's no-longer worth the effort. I'm having a great life on the 'outside', enjoy it!