I did a "practice ER" when I retired from the military at 43. Going from an unbelievably stressful j*b in the Pentagon to an utterly relaxed lifestyle took about a weekend. The pleasure of getting the local newspaper delivered along with the WSJ every morning, then sitting with as many cups of coffee as I liked, for as long as I liked, before starting my day was simply as good as it could possibly get.
After 4 or 5 months, I started getting antsy and looking for something to do. So I got a civilian j*b (in a completely different career field), and actually enjoyed it for a number of years. But when the company got bought out I volunteered for the first round of layoffs (I was 55 at the time). Much to my delight, they accepted, gave me a nice severance, and I went into full-scale ER with never another thought about w*rking again. For the second time, the transition was about a weekend.
Needless to say, as soon as I hung up my commuting shoes, people started calling and asking for consulting time. I have always made it a rule to never do more than 10 weeks per year in that role, and only on projects I truly enjoy, so it's really just a hobby, not actual w*rk.
Since I know you slightly, I would venture to guess that you will find your experience to have at least some slight parallels with my second ER. Nothing to worry about in the least!