I used to always be this way in my younger years. I'd form attachments easily, get really upset over things while desperately trying not to let it show, etc. It was horrible, because I always got the impression that I "felt" far too much for a guy. That's embarrassing on some level and puts you at a disadvantage because it's so much easier being the one who's stand-offish and can take or leave everything.
These days it's a little easier, but only because I've had so many disappointments and awful women in my life that I'm more or less de-sensitized. Long-term chemical lobotomization by way of SSRIs and benzos has helped too.