Guinea pig owner for 2 years, now hes terrified of his cage?

Hello, I've had my guinea pig oswald for a year and a half now, just until 3 days ago, hes been happy, content and just joyful, popcorning everywhere and squeak whenever i talk to him, but the last three days, we had a black out and 30 seconds before that black out oswald literrally jumped out of his cage (i built him a C&C cage, it has no top) and was so scared, i havent been able to get him out of this funk for 3 days... hes still eating and drinking but not as much as before, when i take him downstairs to hang out hes just fine.. doing his tricks for his veggies and everything, just fine... but when i put him in his cage again, hes terrified... this morning i had to add a top to his cage because last night he jumped out when i was asleep, i found him under the bed!