Ah, don't beat yourself up. I have done this and it didn't work out that well. That's the problem with old friends, there is always the history and you might both see it in different ways.
Could be that he isn't interested at all. Could be that he's interested in sex but worried that you want more and doesn't want to hurt you. Could be that he has feelings for you but the situation is too complicated for him so he's distancing himself. Could be he has several women on the go or on the back burner and another one is more interesting.
The only way you'll know is if you ask him directly what he wants. But I would back off a bit first and wait and see what he does or says. If he's not initiating contact at all then he's not that into you. Of course if it has been a while then it's fair to ask him what's actually happening between you, but don't get into a pattern where you're only ever the one contacting him.
So a tip I got on mumsnet years ago when I was tying myself in knots over some guy: Never give more than 25% of yourself to another person.
That does NOT mean (as I originally thought, and immediately discounted) that you should lie or hide parts of yourself or pretend to be somebody you are not. It means that there are important things that it's essential we create for ourselves rather than relying on a relationship to provide them for us. Happiness, sense of fulfilment, self pride, security, plans for the future. Don't let more than 25% of any one of these things rely on another person.
Happiness - yes it's okay for a relationship, friendship, flirtation to make you happy but have other things which make you happy too. If you're lacking them, then create them. A hobby, a project, other friendships, work you enjoy, something that you used to enjoy but don't do any more. Look on the "small things which make you happy" thread for inspiration.
Fulfilment - usually we get this from a sense of something done well or something being "right". So I would look: Career kind of things. Either making a plan so you know where you're headed, doing some training, attempting a promotion, looking for a job/new job. Parenting can be fulfilling especially if you feel like you're doing well. Get on Pinterest and find some nice easy free summer activities to do with DC (or if pinterest makes you feel like a failure, back sloooowly away from the computer and get a book from the library instead 
) Get your house in order and decorated nicely.
Pride - similar to fulfilment but often we look to relationships for this because this is the whole compliment thing - we don't allow ourselves to really believe what's good about ourselves unless somebody else says it. So either make a list of your good qualities and remind yourself of them every day or make a list of things you've done in the past which made you feel really good and do more things like that. If you're brave, ask your friends and family what things they like about you and offer to do the same for them.
Security - difficult if you do feel insecure but it's worth sitting down and working out how you will support yourself for the next X years and how everything will pan out - just helps you feel more in control.
Future plans - the realistic, the idealistic and the crazy ones. And work out the steps to make them happen and start doing them, even if they are tiny. Just plan for yourself and the DC - if the right man comes along they will fit into them, and if they don't, you'll have a great time anyway.
If you have those things even half sorted, you'll have yourself a great life that any man would have to be pretty spectacular to be allowed any space in it. Which is good! They also make you more interesting AND keep you busy, so you have less time to obsess. Every time you start obsessing or worrying, do something else. Get off facebook, or whatever, and get your 75% of yourself back.