What was the cause of my hamster's death, help?

Oh sweetie, I'm so sorry. I have had several hamsters in my past, and they all died painful deaths. I think your hamsters death was either caused by a disease he got from where you got him from, a pet store probably, or maybe it was dehydration, because there are a lot of cheap water bottles out their. The best thing you can do now it get another hamster or pet so that you can let this into the past. If you do decide to get another hamster, get another cage, waterbottle, bedding, food dish, or anything that your hamster touched because even if you wash it, the disease could have spread and you can't just get rid of it with soap and water. Good Luck!!!