I've developed a lateral epicondylitisand can't make jewellery anymore, at least until it gets better (which can take months). I'm about to undergo a series of painful steroid shots right to the elbow and physiotherapy. Fantastic.
I'm also not allowed to swim, and my artistic and professional activity needs to be reduced to minimum, because I use this arm for everything, not just crafts: painting, guitar, illustration, cooking and housework.
Ewch. Hope it heals well and fast, but make sure you let it heal properly before using it again! It's the difference between months of downtime and the rest of your life! (Sorry. Speaking from sibling experience.)
Sorry to hear that! I hope you feel better as quickly as the condition may allow it... did you develop it working in your jewelry or do you actually play tennis? Meanwhile, I know everybody will tell you this, but do read, watch movies, comfort your mind if your body can't follow for the moment... hugs!