I have travelled alone and with company and lived abroad, so have done a variety of things. As others have said the pleasure of going alone is freedom of choice in times and places, and a halfway house to try this out might be courses in interests you have, where you learn more but are free to come and go as you please. Then I have been on Fred Olsen cruises, which again have many different things to do on them and you can do a lot of things and meet people , and bolster your confidence in travelling alone.
Another possibility if you drive is to choose a town or country area that you dont know and then get a b/b there. I am interested in art and music and gardens , so there could be an art exhibition or garden festival happening. That way you have one longer journey and then you have the freedom to go about and discover things from a base, but not committed to being back for meals so you have the choice.
Perhaps sounding a negative but there is also just thinking , if someone said you could not travel anywhere any more , where or what would you feel you had missed out on? for example at my age and with the various hassles I would not think of flying to New Zealand now. So that might make you realize that there is somewhere you really would like to go to and look into doing it while you can. Travelling alone for many years I think that there are a few things that matter. I am safety conscious in not carrying lots of things obviously, that might be snatched, wear suitable and appropriate clothes , always with a scarf , head covering etc, but most of all just go on my way feeling I have the same right as everyone else to be there. That sense of confidence and expecting everyone to be decent in the first place , has meant that I am fine going into cafes etc on my own. The more you do it , the more you relax into it. Try it out, go to a cafe, or a pub you dont normally go to and get a coffee. Maybe have your paper or your phone but look around and listen. You can see and hear people together having a good time, but also families or groups that are moaning or complaining or spending for ever making decisions and be glad that you have no one to please but yourself. Go on start today and good luck