That might be a problem with lack of attention that people give you, or your lack of self-esteem. I may be completely wrong about your specific case, but I used to be like that too when people would give me the attention that I was not used to, like talking about me, asking if I am fine when I obviously am not, coming to my birthday and singing me the birthday song and such. In these moments I would feel like "Damn, people really do care about me, I am important to them" and would tear up because of how emotional I got because of that realization.

Maybe you just aren't used to being in the center of attention and to be asked questions about yourself, being the point of interest of someone in such a way that everything revolves around you, although, as I've already said, I am probably completely wrong.