Numb fingers and chattering teeth

Neck felt a lot better this morning and managed a short ride in the driving snow of Sussex. My return to training was cut short by a thorn puncture (hawthorns being trimmed along the side of the road). This proved my downfall and although it should've taken 5 minutes to fix, a wet innertube and freezing temperatures made the patching process impossible. After 2 attempts and 40 minutes standing by the side of a B-road in the snow my fingers were completely numb and core body temp had dropped to the point I had chattering teeth. This resulted in me calling in the cavalry to get a lift home. Pathetic.  Made all the worse by the fact that just before leaving the house I thought shall i take a spare tube? No, won't need it.