<human>: So about two months ago I started talking to Mattias [20, M] online. We hit it off great, we texted every day, and once we actually met things picked up even more. I was nervous about dating a younger guy, since I've only been with guys older than myself. But it seemed to be going good at first. Then, it started going bad.

It was about the time he started asking me 'what this was'. I liked him, a lot. We joked a lot, enjoyed each others' company, we were very physical after the third week, it was so hot... I could have seen him as my boyfriend. But because it was going so well, and kind of fast, I told him that I wanted to take it slow, and that I really liked him a lot. I didn't want to jump headfirst after such a short period of knowing each other. But I tried to make it clear that I really liked him and wasn't interested in anyone else.

Here's where his age starts to show I guess. He got really cold after that. He didn't understand where I was coming from, and took it all wrong, thinking it was personal or that I was trying to let him down easy. No matter what I told him, he couldn't be convinced how much I liked him.

So as he started pulling away, not wanting to see me, not texting back, I got insecure myself. Understand, I've been in plenty of relationships. My longest was 7 years. This was really nothing new to me, but I really, really liked this guy I guess. But everybody knows, insecurity isn't pretty, and ultimately, Mattias stopped replying altogether.

So all of the sudden, I'm feeling rather heartbroken and shitty. It's been many, many years since I've felt this low about a 'breakup'. His actions clearly indicate a certain lack of emotional maturity, which is what I was afraid of, given his age, but... I know we never officially became boyfriends, but his misunderstanding and sudden departure hurt me enough to make me cry like an idiot. I haven't cried over someone since high school...Thus the title.

Provide a brief overview of the text.
<bot>: Guy misunderstands my intention to take things slow, shuts me out, am heartbroken for the first time since HS even though I know better... Why does this shit feel so bad? I didn't even know him very long.