I am wearing a retainer and it has a crack in it. What should I do?

Hello doctor,

I got braces almost three years ago, and I ended up with a perfect smile. I wore my retainer nearly every night, but on an occasion where I forgot to wear it, it would be painful the night after and felt like the teeth had moved. Fast forward to now, I have still been wearing my retainer, and found that whenever I forgot to wear it for more than two days, the teeth would move (almost noticeably), and when I used the retainer the teeth would go back to normal. Recently, I found a large crack in my retainer and found that even after wearing it for a few nights, two of my teeth are slightly out of place. I understand that I need a new retainer, however, if they were to make impressions of my teeth now, the retainer would keep the two shifted teeth permanently shifted. Is there a way to clone a retainer? So that my teeth would go back to being perfect using the original impression, rather than an impression of my shifted teeth.