Like you , I took early retirement at 54 , and after 6 months was bored out of my mind.
I was already a volunteer at the Samaritans , had been there for 5 years, so I increased my sessions there .Then came a house move to a different area and I volunteered for training at a CAB,worked there for 3 years as a volunteer and then was appointed as a part-time Tribunal worker(getting paid again was terrific.)Did that for 21/2 years until I moved house again.
After unpacking all my bits and bobs went to the local F.E college and signed up to do Indian Head Massage.Loved the course ,and it was free for golden oldies.
So now do that free for anyone who I know in my area.
Then looking on the net found that my local uni did free courses and did one in Life Coaching., now have a small business doing this hours to suit me , holidays when I want and I generally work no more than 1 day a week.Useful for keeping the brain active.
After much thought am now thinking about a new dimension and will be scouring the net to see what there is.
So my advice to you would be go for it , use the net, local colleges , find out what is on offer,or do some voluntary work, and enjoy your retirement.
I honestly now don't know how I found the time to work .Sincere good wishes and the very best of luck.Brenda.