Major crate training regression in 6 month old

Hi everyone, as the title suggests my 6 month old toy poodle has undergone an extreme regression in crate training. Since around 8 weeks, he has been sleeping soundly in his crate with a Kong both when I bring him up and after he comes back from the toilet, with me also going to bed, in what has been an extremely consistent routine. About 4 days ago, he started crying, eventually devolving into screaming, in his crate after toilet breaks, but now after he's placed in at the beginning of the night too. It has gotten to the point where I am sleeping on the couch as he will not tolerate the crate, even if I am directly in his line of sight. I'm considering going back to basics, as well as buying him teething gel as I suspect this might be the root cause, but I am at the end of my tether and finding this really difficult, would appreciate help here.