Oh crap. Well that changes things slightly.

Bring the basking temp back up. Keep it about 130-145 at the hottest spot. The ambient temp sounds about right 75 (cool end)-90 (warm end) during the day.

They do fine on crickets. Just feed them a lot. My ackies (even the adults) eat at least once a day. I do supplement with pink or fuzzy mice once a week. They'll also take baby quail, bird, snake, or gecko eggs, worms, roaches, and about anything else that fits in their mouths. Personally I think they're more fun than some of the bigger monitors and you don't have to worry about hospital visits, huge cages, expensive feeding bills, etc.