Steppe Runner is suddenly sick

[Phil72]

Not a gecko, but I need urgent help with this:
My steppe runner, who I got as an adult and have had for a few years, has suddenly become very weak, lethargic, and has lost a lot of weight. His tank conditions are correct and the same as they have always been. He used to be very active and a very wild eater, now he does not run away when I put my hand in the cage and he has to be fed by hand. This has been happening for a few days now and he is getting worse by the day. Please tell me of any ideas you have for what may be happening and how I could bring him back to health.
Update: This morning he wanted to eat when I hand fed him but was having trouble chewing.
Pictures: https://imgur.com/a/Ti7GY

 

[Seth9999]

I'd go vet immediately with those symptoms,

 

[Seth9999]

I'd go vet immediately with those symptoms. Howes his supplements ?

 

[Phil72]

He gets his food dusted with Repashy calcium plus. Can you please help me to narrow down what the problem is because I can't currently get to a vet? Thanks.

 

[Zux]

Nobody here can safely diagnose the issue(s), to guess and misdiagnose is highly dangerous for the animal.

You will need to see a Vet seeing symptoms this advanced, chances are very high it will not be something you can reliably address yourself.