Cruising solo can definitely be a positive experience. I do not think there is any better travel experience to be able to meet other people.
I have sailed solo, with a partner, and with groups of friends. If I am just going away to relax and read, and not have to entertain anyone, then I always go single.
If you are looking for a good cruise line, I would recommend Holland America as their single supplement is much better than most - generally 50%. In March I will be sailing with MSC and their supplement was only 35%. If you decide to cruise, I do not think you will be disappointed - there will always be other singles.
I will try to answer any other questions you may have.