Life happens. Lots of people have a missing tooth for various reasons, either from accidents, decay/weak teeth, lack of fluoride as kids etc. You wouldn’t know it though, because modern dentistry can make the replacement look so natural. I know someone with a false tooth due to lost it as a teen from a bad bike fall. Even if your reasons are different, it doesn’t matter. It’s natural to be upset, but also remember you’re doing so well now and looking after yourself! Hope you feel better soon!