Congratulations. It does take a bit of getting used to.
I retired just short of 2 months ago. I took the summer off, regardless of what everyone else wanted. I think I can offer up some hints.
First, learn to say no. The line I'm favoring now is "I'm just not comforatble doing that just yet." A trick is when they start asking you to do things on their timetable (and they will), just refuse. If you want to do something, or are willing, do it when it pleases you, not them.
Next keep everyone else off balance. The phone calls I hate most are the ones that start "what are you doing?" I've come up with a new answer for that. Its "just sitting here waiting to die." No one expects that. But I'm doing what I want, not what others want me to do. Unless it benefits me, of course.
I've learned to separate my phone calls into two categories. Those that will benefit me, and those that won't. I have very little interest in requests of my time if its not a benefit to me. I'm sure you already know how nervy some people can get. It gets worse because now they can hide it in "helping you keep busy." Forget it. Its your time, do as you please.
Now if its another retired buddy wanting a fishing or hiking partner, then its OK.
I'm just getting the hang of this stuff. You will too. But retirement is no reason to allow others to manage your life.