You don't have to stop watching the thread. Follow these steps:
1. Go to the settings section for you (click on your name up top.)
2. On the left sidebar, it should have an option that says "Preferences"
3. Underneath "Automatically watch threads that you create or when you reply..." is "and receive email notifications of replies" uncheck that second option.
If that doesn't help you then I'm sorry, and have no other ideas.