How do I regain control of myself after these guys are talking to me?

Just tell those guys that you're not interested, you don't have to give them a lecture, but I bet you would feel great if you just looked at them and said, "look guys I'm not into you, so just back off." you obviously have morals and a good head on your shoulders, unfortunately, some guys don't get the hint and always want what they can't have. You're too good for their crap, and you need to start believing that instead of getting insecure or nervous, because you are obviously hot shitt, and they can't handle it. You tell them that, even if they don't back off, it takes guts to say and you can walk away from them, with a smirk on your face and KNOW that you truly are a classy chick.