Sorry to hear. You just have to think to yourself stuff like this happens and there is nothing you can do about it. You tried your best and did the best you could. Again I'm sorry. =/
I had a Bearded Dragon that died 3-4 days after I got her and after she died I found out the old owners didn't have the right UVB light they were just using a plain Florescent bulb so she wasn't getting any UV rays and the Calcium couldn't develop correctly which caused her to be Egg Bound because her eggs didn't develop right cause she didn't have enough Calcium. I was very upset but stuff like this happens.