Jonesy is right about overthinking it. The feelings of loneliness, that something is missing in your life can definitely eat away at you and affect your success. The problem with a lot of guys is that they feel inadequate and try to use women as a source of validation, to fill a void in their lives. You need to remember that relationships are ultimately about sharing experiences, and we seek people to enrich our lives in various ways. If a woman senses that you feel empty and that she will become a "filler" for your emotional void, what would motivate her to want to be with you? What is she getting out of it? If you have things in your life you enjoy, that you are passionate about, and you can express yourself in a fun, interesting way, she will see that you can enrich her life and will want to share experiences with you.
A nice resource I stumbled upon for dating was an e-book I think might be helpful to you called "Double Your Dating" by David DeAngelo. It goes in depth into the beliefs and mindset you should cultivate when interacting and socializing with women. If nothing else, it can offer a new perspective into the mechanics of attraction and interaction with members of the opposite sex. When I read this book I realized that there were core beliefs, some I already had, that affected my success.
I'd suggest trying to be more fun, outgoing, passionate, and focusing less on trying to "get the girl". Anyone would choose someone they could see themelves having fun with over someone who seems needy any day. Also, look up that e-book, it could help.
