My crested gecko isn't eating

I'm sorry if this isn't the right place to post this but I thought I'd give it a try!! I have a crested gecko that is 5-10 years old (he was a rescue so actual age is unknown) who I have had for just about 6 years. I got him with my boyfriend who was very into reptiles and he was Echos sole caretaker. Well we broke up a couple of months ago and he was unable to take echo with him so his care has fallen to me.

I love all animals but literally know zippo about geckos so I was faced with either finding him a new home or keeping him. I feel a responsibility to him and it makes me feel awful to think that even if someone offered to take him, I wouldn't 100% know that he was going to a great home so I decided to give it a try and do my best for him. His cage was in need of an upgrade so I started by buying him a new one just over a week ago. I know that a change like that can be stressful so I am hoping his disinterest in food is just stress related and not illness related.

I got him a taller cage and transferred everything from his old one into it so it would feel somewhat familiar. Since being in it he hasn't eaten and he hasn't come out from hiding once (he may be coming out at night but I stay up pretty late and haven't seen him at all). I can see him tucked behind the brush so I know he's alive and he looks okay, but he isn't used to being held (though I can pick him up if it comes to it) so I dont want to stress him out further. What seems a bit off to me is that he is normally such a brave guy and it's not like him to hide like this. He has had cage changes before and he did not hide for this long. He still has his tail which I was told is pretty rare for a guy his age and he's normally not so hesitant to climb around everything.

I feed him repashy (even though he's not eating it I make sure to change it out so it's fresh if he wants it) and have been trying to tempt him with some banana since it's a fav. But no luck. I'm so worried about him and since I live in a small town there aren't any vets who really know about reptiles so I feel like I'm flying blind a little. I don't know if I'm overreacting just from a lack of knowledge or if I should be concerned. Any help would be soooo appreciated, I feel like I'm doing something wrong even though I have been following the care sheet my boyfriend left for me. If anybody has any experience with crested geckos I would be so thankful for some help.