How do you pick yourself up after getting your heart broken?

I fell for someone who lives in a different country. We met while he was passing through mine, and then he later changed some of his travel plans to come back and see me again.

We saw each other every single day for over a month, he met most of my friends, we went on trips together and overall he was very loving and did all kinds of things that made me feel like we had something that could last beyond a fling. He told me he would be back again.

His feelings changed not long after he went back home, and he only admitted it to me once I confronted him after noticing him become more and more distant over 2 months. He said he found it hard to stay emotionally invested in someone so far away.

I get that long distance is hard and that people's feelings change. I just didn't think he'd lose feelings for me so easily. It hurts more than ending a relationship that has slowly burned out over time, because I just can't make sense of how quickly this happened. And I think a large part of why I got so attached is because I very rarely meet guys I'm genuinely interested in, let alone ones that treat me well.

Have any of you gone through something similar? If so, how did you cope with it? Was there anything that made it easier to accept, or do I just need to let time do its thing? I have a bunch of important things to finish this week and have already lost so much time crying lol.