I must say that you are a very detailed person, I think that your fast started at 7am after your last intake of vitamin C. I believe that your body is in digestion mode anyway for 40 hours after your last meal. If you want to count only Vitamin C being digest which is faster than a full meal and the fact that it will be in your system for at least 6 hours, I would say 1Pm on Friday is a clean break from food consumption.