the thing you did wrong was you keep him too hot, you had too few branches so he probably could not get to a shady place so the light irritated his eyes and thats probably why he keep them close, he went to the bottom of the cage because heat moves upwards to the cooles part would be at the bottom, you had too lite ventilations, you either go for a terrarium with front ventilations and all screen top or a whole screen cage.
you need to feed the crickets before giving them to the chameleon, and never ever have waterfalls inside his cage due they can cause bacteria breeding grund that can harm them.
also vitamins powder and calcium with D3 should only be giving once a month( I dont know how you did this) but plain calcium every other feeding.
keep in mind this things if you are going to be getting an other one
here is something that may help
https://www.youtube.com/watch?v=lKTbUaOQ0aA&list=PL4HFX9PBYVY2eIWT0v3ZgYSk-r76SEujI&index=1