Sorry for your loss. Don't beat yourself up over it though. Sometimes animals are just sick and there's nothing you can do about it. Im sure the majority of people on this site have gone through something similar to you at some point in their lives. I bought a rainbow boa a long time ago from a local pet shop not knowing he was sick and after 3 weeks the poor guy died. I felt horrible. It did get me doing a LOT of research after the fact though. This is what they mean by "good coming out of bad situations." we all learn. what I can say is in the long run, i'm certain you will find another friend and will do a good job caring for your buddy because you seem like you actually care! Good luck and again, sorry for your loss.