I did this in 2014, first time in 30 years. Best thing I ever did and should have done it years ago. A few months off allowed me to clear my head and work out what I wanted to do, and completely changed my perspective. I'm very lucky in that I had a few options appear quickly as what passes for the 'specialist knowledge' I have is in demand but I was prepared to take longer if I had to.
I go through two alternating emotions...
1. Massive excitement at the endless possibilities I will have.
2. Absolute dread and fear that I'm giving up a very well paying (and pensioned etc) job with absolutely nothing to move into, and there are others relying on me.
What doesn't help is the 'rainy day' fund I have, which is in the form of shares in my (soon to be ex-)employer, have fallen by around 25% between when I resigned and now. It's a classic "all (well, most) eggs in one basket" situation. I could have cashed in many of them before now but kept them in place in order that I didn't fritter the resultant funds away. In this regard, my timing couldn't have been much worse.
Our car also got written off recently meaning we had to replace it. Ours was old and crappy having covered 160,000 miles, most of which were on the motorways between Somerset and Sussex, but it was still very reliable, so we'd decided to keep it as long as it kept going. The accident meant that happened sooner than we would have liked!
Oh well, onward and upward!