Getting over attached to people too quickly

I met a lovely man while I was on holiday (he was from and lived in the place I was on holiday), we met first time at an event and got on well so went on a date two days later. During the date we slept with each other. We met up with each other the following two days of my holiday. We did not sleep together on these occasions but would hug/hold hands/kiss some of the time and generally get on well. On the evening of the final day I had to leave to go home as I live and work in a different country many miles away so we said our goodbyes. We have emailed three times but the correspondence has superficial and unflirtatious. However, I have initiated every correspondance, and he has returned my emails (sometimes very late on) implying that rightly so he has probably moved on with his life and forgotten about me as this was a very short occurence in both our lives. I have not seen this man for 18 days but I still cannot stop thinking about him and completely feel heartbroken that it has had to end and pretty much think about and obsess about him all the time. Obviously a long distance relationship would be impractical as the cost of the flights would be extortionate, and neither of us are especially wealthy. However, we have never discussed this. I feel really pathetic considering I only was involved with him for three days yet I still completely feel heartbroken and miss him so much. Is this normal?

he sounds like a married guy, and you were the fling. let go. and smile, you were happy for 3 days :)

Thanks. However this was a young man in his early 20s ten years younger than I. It is a same sex relationship. However it could well be that he is in a relationship. Before we had sex he was very lovey dovey afterwards in the following days he was less so although still kind lovely and hospitable. What does anyone reckon?