Retainer doesn't fit one tooth

I have a permanent and an overnight retainer that I wear religiously. However my teeth still shift. From 0 {content removed} 21 I have had severe lung issues that made me swallow and use my mouth weirdly just so I could breathe. I can not unlearn that because I still feel like I am suffocating on choking on my own throat slime. (sorry for the weird description). I swallow against my teeth. So I errode the permanent retainer away about 5 times in 6 months. Sometimes I don't notice it has come lose. Therefore it is very important that my overnight retainer stays as perfect as possible. Without it my teeth will be crooketh in a matter of 2 days. I have had braces for 8 years in total now and having crooked teeth again makes me have a panic attack. Some teeth are thicker than the others so every miniscule bit of movement makes my smile look weird. Recently I have noticed just one tooth of mine doesn't fit my retainer. The retainer glides on smoothly it just seems like the tooth is too short. All the other teeth fit nicely so using a chewy doesn't help. Now in a week I need to make a new retainer because this one is starting to look very dirty. But I don't want one tooth to be crooketh In the new retainer so that my retainer forces that tooth to go even more crooked. How can I make sure my tooth will still fit the retainer so I can wear it 24 {content removed} 7 till I get to bite the clay like stuff and the retainer will turn out perfectly???