If it's bothering you that much fuck a few prostitutes.
I'm not being facetious here at all, if it's merely the simple act of sex that you are craving then there's an industry for that. Find a good one and she'll make you feel good.
If it's sex and all the emotional connections that go with it (whether you're in love with the person you're having sex with or not) which you can never get from sex with a prostitute then that's a bit more difficult to address. You need to be putting yourself out there and meeting new people first and foremost. Whether it be through hobbies, interests, mutual friends, internet dating or whatever....you can't make a sale if you're not in the marketplace (sorry I study business/economics). It's a numbers game to be frank, there's a certain percentage of people out there who will be quite happy to have sex with you, but it will never happen unless you're actually meeting them...and that means 'going through the numbers' to put it crudely.
To be perfectly honest I would probably fuck a few prostitutes just to get the whole lack of sexual contact out of your system and give yourself some sort of sexual confidence. When I say prostitutes I don't mean trafficked girls or crack whores being pimped, I mean girls that are doing it out of their own desire to engage in the industry. You need to get 'back in the saddle' as it were and regain some contact with females for sure.
You also need to address the regular confidence issues you clearly have, we would need to know a little more about you to give advice on that one. The extent to which you are dwelling on the missed opportunity is indicative of some sort of over introspection that is becoming as well.
Anyway, that's my two pence, apologies for all the cliches.
*awaits flaming