Major teen guy troubles

Hi so I've had like I don't know maybe 3 or 4 guys that I've spoken to often and thought that maybe we could be something more, then all of them just end it, or say that we don't have a thing, or tell me I have the wrong idea, when I'm absolutely certain by what they were saying to me that they liked me. I don't know what I'm doing wrong and its completely killing my self esteem!!?? Can anyone help out?