OP,
I'm in the same boat as you, and I know how crippling it can be to feel so alone and undesirable. It's utter sh*t, believe me I know. Fact of the matter is, if you're living a healthy lifestyle and are engaging with people, somewhere along the line you WILL meet someone. Unfortunately it is just a matter of time. Follow the advice I wrote in my post above, and you should see some improvement.
If nothing else, do not convince yourself you are not good enough. You do not want to get to the point, like me, where you accept you will be alone forever.