without sounding awful, do get checked out just in case he cheated on you before and gave you something. It's unlikely, but better safe than sorry.
Being single can be fun. I'm happier now than I ever was with Nate's dad (my boy). I don't have to bail him out, I can buy whatever I like without having to answer to anyone, I can do what I want when I want (within reason as I do have a wee one tying me down, but you don't!) I get to enjoy my hobbies without fearing being mocked, I can cook whatever I like without hearing moaning "but I don't like veg" like a 7 year old. There are so many great things, big and small.
After he bogged off I said I wasn't going to do what a lot of my friends do which is to go from one man to the next in a fear of not being with someone. At the time it was because I do not want that for my son - having men come in and out of his life, but now I have some self worth back, I don't want it for myself either. If I should meet a nice man in the future then so be it, I won't just tell them to bog off for the sake of it, but my standards are now very high because not only is it what my son deserves it is what I deserve too. And You deserve it as well. Let the girls who will go with a taken man in a car park and what have you have the time-wasting losers of the world, there are many wonderful men out there waiting for you
in the mean time, get to know you