I "retired" at 57 years old from working at a major University System for 30 years. But I had been in the work force for well over 40 years. Whether you enjoy, or have difficulty adjusting to, retirement, depends on how much your sense of self worth and identity is wrapped up in what you do for a living as opposed to the rest of your life outside the work environment. Though work gave me some sense of satisfaction, I always tried to keep it in perspective with the rest of my life, and generally speaking it was always just a means to an end for me. I earned money to be able to do the things I really wanted to do...and those things took many forms over the years. I do not miss getting up, driving in traffic, putting up with incompetent a-holes in a highly political environment where I had a lot of responsibility and no ultimate authority. I do not miss having to kiss butts simply because of the position they were in, and having to keep my questioning to a minimum despite their incompetence.
I thought I could find similar work in a smaller work environment, but after getting three interviews in three years, I have given up on that. I only miss the money, as my pension does not allow me to live at the same level as when I worked. I tried my hand at sales in two different environments...hated both of them. So, in Sept of 2010 I quit beating myself up over not having a job and have enjoyed every minute since. I turn 62 in September of 2013 and will begin drawing my Social Security, which will be a little extra money to supplement my pension. If I had gobs of money, I'd be traveling to all those places on my Bucket List, but I don't, so I have to pick and choose. I have my photography, fishing, and motorcycle to keep me busy. Also, piddling around the house occupies some of my time, though I am tired of maintaining a big azzed yard, so will downsize all that in the next 3-4 years to free up funds for more travel. There are many things a person can do...volunteer for something you enjoy or believe strongly in; take a PT job if you can find one that you enjoy; explore a hobby you either do now, or have always wanted to do.
Take advantage of the opportunity retirement gives you to spend more time doing all those things you could not do because you had to get up and work every day...let those things define who you are and don't worry about it.