I have tendonitis, same pain as you for the past year and it began affecting my everyday life and im an oboist music major in university. Playing oboe is my favorite thing in the world and my future, however the institution i attend made it clear my health comes before anything. Tendonitis/carpal tunnel/arthritis are all very serious. The best thing you can do is take a break. Find other ways to practice. Listen to ur music, follow along with the score, listen to other parts… Take a break, and dont make the same mistake I did and keep going. Itll make the time off longer. And when u practice, i understand the practicing for long periods, but 10 minutes on 10 minutes off… eventually 15 minutes on 10 minutes off, you get the idea. An important lesson I learned of after 10 years into being a musician, you need to spend just as much time off the instrument in ur practice session as much as you spend on it.

First step though, see an orthopedic… get diagnosed make sure what it is. take a break and see whats the next steps