DNF. First time i've ever pulled out of a race

I was gutted. Think its just a strained/pulled calf muscle. Went over on bad ankle just after stream crossing between checkpoint 1 & 2, well taped so seemed to get away with it but then calf started niggling a few mins later so not sure if related. Got steadily worse til I couldn't run on it at all.
Seem to be walking ok today, so reckon thats a good start point for my 3 peaks training!