It sounds like you rush into relationships because you are lonely. This is not good because when you had sex with someone so soon, you get involved before you know if you are comparable, then when it falls apart it is more traumatic. Sex too soon can mask the fact of basic incompatibility, take it slower next time, much slower, get a dog if you are lonely, seriously. Most women are turned off by needy men, so you will scare off the good ones.
Do not have sex on the first few dates, get to know her as a person, see how she behaves, decide if you want that in your life, It would be better to wait a few months, see how she acts in different situations, probably too much to ask of you, but it would be better for all involved. Be especially cautious if she has children. Little ones get attached, and then it is traumatic for them when you leave, you don't want to do that to a child. Don't move in until the relationship is well established. If you are a decent guy, you will find somebody, but don't expect her to fill all your needs, get out there and find some more guy friends also. This will help you increase your social circle and improve your chances of meeting a girlfriend.
Hang in there, you will find someone. The fact that you are asking advice shows your heart is in the right place. My husband and I are two nerds that just happened to find the perfect partner in each other, if we did it, there is hope for everybody!