Was it the Achilles? There is another little one that runs close which will fix itself after a few weeks. I had it pop and thought someone had hit me with a hockey stick… thought it was my Achilles then had the scans and turned out to be plantaris or similar… can’t remember the name… anyway most people don’t have the tendon at all and it fixes itself with rest/physio.

Hope that you have a speedy recovery :)