I can only base my advice on intuition, as I am on my first Master-Cleanse day 4, but it seems like you have it down. I guess all I can suggest is that if you see yourself not feeling good in time to travel, then you should break. Or if you think it will pass in a day or so, stick with it. From other fasting experiance I have had I know that the weakness is a sign of detox, so drink up. See how you feel tomorrow. You know your body better than anyone, and you also know what your intentions towards it are. Regardless of what you choose you should always be happy with it. Great Job!