I felt a burn like fire.... What stung me?

I was chopping trees and felt what I describe as a coal of fire on my leg. Then my entire leg was on fire and tingling. Before long there was localized swelling the spread throughout my entire leg. The burning and tingling got worse and where the initial burn I felt was I noticed my skin was pitted. There was no fang marks or sting marks. Within 45 minutes to an hours I became nauseated and had stomach cramps with diarrhea. Throughout the night I experienced muscle twitches and cramps. WHAT STUNG/BOT ME?????