Lostintheworld, the above response is insightful and factual, on every level. Going onto dating sites will not solve whatever is going on because everyone on those sites is putting forth information that is typically untrue and designed to generate responses. Plentyoffish.com is a repulsive site where sexual "hookups" is the main goal. If you're interested in sex, only, save up your money and head to a well-managed bordello or "escort" agency and keep in mind that it's a business transaction regardless of how you might "feel" about the escort providing the services.
If it is a true relationship that you are seeking, I agree with the poster above and begin working on your Self (Self = soul or inner self). At your age, there is absolutely no reason to feel "lost in the world." This is the best time of your life because you have the energy and freedom to accomplish anything that you put your mind to, including rewiring your thinking, perceptions, beliefs, and self-esteem. Building up your own boundaries and working on whatever issues that you might have will not only benefit you, but attract a partner that will enhance your life, as you will enhance hers.
Speaking from a woman's point of view, it is not the man who is needy, desperate, easily-manipulated, or depressed that catches someone's attention unless she has her own dreadful issues, just as the poster mentioned, above. NOR is it a man who is overbearing, dismissive, abusive, arrogant, or heartless - what most grounded, balanced, and emotionally healthy women seek is a partner and companion who "gets it" about Life, living, and growing older and who realize that rabid sex isn't required as the basis of a healthy and long-lasting relationship. There are also women who seek men out with the belief that they will be provided a specific lifestyle, and they can be avoided by a strong, balanced, and centered man regardless of how attractive the women might be.
Slow down. Take stock of what your immediate vulnerabilities are - neediness; self-esteem; regret; control/anger issues.........whatever. And, just because you haven't "gone off" on someone for years does NOT mean that anger issues aren't present. I didn't argue with the second exspath because I was utterly codependent and I had multiple personal issues. The day that i discovered that he had used my income to finance his extremely deviant lifestyle was the day that all of my disappointments, neglect, dismissals, ridicule, and previous abuse erupted like a sleeping volcano, and I beat the absolute shit out of that man and was arrested and charged with domestic violence (later dismisssed). So......I kept everything down and never spoke my mind, but I was a seething cauldron of anger, fear, and sadness. So............take a close look at your vulnerabilities, start working on them one-at-a-time, and post back in a few months.
But, I would strongly discourage dating sites for anyone, not just you. People on dating sites have an agenda, and it is a rare event that people actually connect on a healthy level. And, healthy relationships are absolutely possible, but they must be earned, not purchased.
Good luck to you.