Angel,
First, the "don't text more than twice a day" thing is nonsense. Just don't text someone who isn't texting you back, and don't text really emotional stuff to them, and try not to whine about your problems via text, because those things should never be handled via text. It's fine to say "I had a bad day, and explain why, just don't go on and on about it.
I second the therapist suggestion. Obviously you have some anxiety that you're dealing with. People on here are largely saying "You can't be an emotional mess" around a guy, and that's correct. Most guys will be incredibly turned off by clinginess and anxiety. Partially because a lot of people simply don't want to, or cannot, or don't know how to, handle that kind of emotion from someone. And saying that you shouldn't feel that way is all well and good, but you also have to be able to process the emotions and feelings you're still having. And I don't think people just telling you not to worry about stuff is going to solve that. You talk about having low self esteem, and I'm guessing there's some insecurity there to deal with.
Are you, or have you considered seeing or talking someone, a counselor or therapist that you could talk about your concerns with? It can be particularly helpful when dealing with relationships. It doesn't mean there's anything wrong with you, just that you may need another perspective to help you figure some things out. I (like many here, I suspect) had some of the same issues you're referring to, and I see one sometimes as well, and it can be a very nice resource to have. It's certainly helped to make me a more well rounded, secure person.
Constantly complaining about issues and worrying is definitely a turn off. That said, a guy who won't at least listen to your problems on some level, provided they are legitimately problems, probably isn't worth your time if you actually want to date him. It's true that a lot of men want something physical, but you seem to be in this for dating purposes, period. And getting to know someone, and their issues, is a part of dating, even casual dating.