So basically, HerzSam and that guy are right. And I'm not going to fucking sugarcoat, it doesn't help anyone.
We women right, we can smell desperation. We don't like it. It's deeply unattractive to basically all of us (apart from the weirdos who are themselves so desperate they go out with the first person who comes along and end up dead or whatever. I digress).
How do you know that being in a relationship will be the magical cure all your life needs for you to be happy? Why do you even want one that badly? Is it because you seem like you're the only single person ever? You're not. Is it because you don't want to die alone? That's stuff to think about when you're like 70 and have no family or friends.
How can you even be happy in a relationship if you're not happy with yourself first? Being single isn't about finding the next person for a long term relationship, it's about learning about yourself, enjoying your own company. In the words of Belle de Jour in her frankly brilliant book "Guide To Men" (for women, but to be honest most of it applies to both sexes) - "be who you want to get in a relationship" and "fake it until you make it". So, you say you're not overly confident, but it's not actually hard to give a pretence of confidence. Stand straight, smile when you talk to people, make witty conversation if that's your forte. And if you're determined to get a long term relationship, you've GOT to stop pining after girls who are taken or don't seem interested. Ask them, if they say no, chalk it up to experience and move on. No is not the be all and end all of life.