my baby suddenly died?

I’m not going to post of a photo of him since I’m still really grieving, but I checked on my frog, cheeseburger, this morning and he was in his water dish completely alive and well, I thought it was unusual that he was awake in the early morning but brushed it off. though I just checked on him tonight to feed him (over 12 hours later) and he still in his water dish with an isopod on his head, I thought it was cute till I noticed his eyes were uneven and pupils really small. I looked more at him and saw his back legs kicked out and i immediately took him out to find him completely limp. he wasn’t responding to anything and was starting to look more bloated. I tried everything to wake him up for nearly ten minutes but he was already gone.

I feel so incredibly heartbroken and I’m so scared I did something wrong or he drowned?? he’s never had trouble getting out of his water dish before so I don’t know what happened? I feel so sick. he was turning one in November. did I do something wrong? I feel so horrible. I know he’s a frog and not like a dog or cat but I really really loved him and his personality. he was my baby really.