ADVICE I’m not sure if my rat is sick or stressed

Hey, I’m new to this website. I’ve created an account to look for advice. My rat is almost 2 years old and seems to be breathing very fast. He currently has a very over grown tooth that sticks out his mouth. He still eats and does his daily thing everyday with his tooth like that. In 3 days he has a teeth trimming appointment which will be his 4th time. I’m not sure if he’s stressed because of his eating (I’ve been feeding him soft foods because he can’t eat his normal feed) or because he’s old or if he has an infection. He still comes out his cage and plays but gets tired very quickly. I’m guessing he’s just getting old and tired. I am pretty educated about rats as I’ve had multiple but they never had a problem like this. So if anyone wants to share some other advice on what you think that would be great. Like I said the soonest vet appointment I have for him is in a few days but I am still worried .
Thank you!