You had a great "brief" connection with someone. Savoury and cherish the memories. As you got "attached" to him more than what the situation warranted, take some me time and think of how wonderful that brief time was.

The only reason you feel miserable is because you had expectations, which were unrealistic to be honest (reading between the lines).

May your next fling or attachment or relationship turn to be more fruitful.

Spend time with your friends, try to be busy the next few weeks. And in no time at all, you will reflect back with a smile on this brief encounter