How are my legs moving?

I don't know where the strength comes from sometimes... When I was in Italy three years ago (getting over another ex), I swam all the way out to that buoy just to prove to myself that I could do it. When I reached it and looked back to the shore I didn't know how I was going to make it back, it was a lot further out that I had originally thought. I made it back. Where did I get that strength? Why am I always heartbroken in Italy? When me & J broke up my legs kept moving and I was able to walk away. It was as if they were separate to my body, had a mind of their own and just kept going... inside I didn't feel strong.