I can really relate to your thread, because I have felt the same way so many times. I'm an introvert. I don't like parties. I'm not the "fun guy who makes a girl laugh". I didn't have my first relationship until I was 30 years old. I've learned a lot since then. When I dreamed of relationships, we worked in perfect harmony. In real life, the other person isn't always on the same page as you. I had this moment of, "I found someone. Why am I not insanely happy?" I was in the beginning, but it leveled off.
The other posts have done a great job of addressing that it's not going to solve all your problems, and a good chunk of happiness comes from being content with how things are in the moment. What I wanted to add is practical ideas about finding someone that I wish I understood at a younger age.
1.) You don't have to change who you are. You don't need to flip your personality to an outgoing partier. However, you will need to be willing to step out of your comfort zone. You may need to open up a little bit. Do you think you are so reserved that you aren't letting people get to know you?
2.) Being desperate is one extreme in searching for a partner, but being too passive is another extreme. You can't force things to happen, but you have to be open to them happening. You don't want to ask out every guy you see, but you don't want to hide in a place where you aren't meeting guys at all.
3.) Don't rush in to a relationship. I've made that mistake. We started off very well, but as I got to know her better, we found out we were not compatible at all. It's easy to fall into the trap of creating a fantasy and dreaming that it's all going to be perfect because you had a good initial encounter with someone. Be mindful of that. I remind myself that it takes time to get to know people.
4.) No, God is not punishing you with singleness for being bad. He doesn't "reward" you with a mate when you're good. Lots of people who are living wrong find someone, and lots of people who are living right don't. Life often isn't fair, and believing it to be so is setting yourself up for misery. Don't approach God in that transactional fashion.
I really do feel for you, because I can relate to these feelings very well. You are not cursed to be alone forever! You can, and will, find someone!