How to make C# easier to play

Hi! I'm a clarinetist who's been playing student for 5 years, and when I began my 3rd year, C# was really easy to play, but B Natural was hard probably because it was Covid and those werid masks to play were, well, interesting. When I came back to start my 4th year and till now, I got a different clarinet, easier to play B natural, but half the time I play C#, it's a squeak. Is this just a me thing or does anyone else experience this???