Hello, I went running today and about at mile 3 suddenly I felt goosebumps on my arms, tingling on my head....my vision started to brighten...I stopped running, felt nauseus, sat down, put my head in between my legs for about 10 min. But I forced myself up because I needed to get home. I stood up walked across the street and am told that I started walking in the middle of the street onto oncoming traffic and then fainted. Was this dehydration? I just don t understand why my eyesight brightened.....