I used to think that being alone and single was the worst thing in the world before I met XABF. After a couple of years, I started to feel lonely whilst still in the relationship. Then it got to a stage of treasuring my alone time because it meant that I didn't have to deal with his drinking.
Now that I am single after nearly four years, my outlook has changed. It's pretty awesome to be single! You can do what you want when you want, without having worry about how alcohol is going to fit into your plans. The other day, I went to Burger King. Usually I would've got it to take away and sat in my car to eat it before resuming my shopping. But I decided to eat it in and guess what? It didn't feel weird at all!
If I were you, I'd book myself a table in a nice restaurant (perhaps one that you've always wanted to go to but never did?), take a book and enjoy yourself. Afterwards, take a nice long walk to your favourite place in town, grab a coffee or hot chocolate on the way and finish off reading your book. Or if it's raining, hit the movies! I missed out on seeing a lot of movies because XABF 'knew he wouldn't like it'.
You've literally got the world at your feet now. Your son is obviously happy so you should be too! Like you, I've got 3 or 4 close friends and my family as a support network. I think having a few close trustworthy friends is far better than having loads of friends who really don't care about you.
You might miss AH when you're doing things on your own but just remind yourself of what it would be like if he was there. Sometimes when I'm trying to sleep, I miss snuggling up to XABF. Then I remind myself that since March, he would hardly touch me at all - and if I tried to simply have a snuggle in bed, he was push me off saying that it was too hot for cuddles. So I stretch out and enjoy the extra space instead!
Figure something that YOU want to do and do it. There is nothing holding you back now!