This also happened to me, I was on day 10 of a Urine Fast and was drinking Spring water. About day 6 I started getting very acidic, by day 8 I was going into severe acidosis, Headaches, extreme lethargy, nausea to the point of feeling like puking, and began to manifest bad acid reflux, I was Urinating about 20 times a day, Still I continued. I tried switching my water to 9.5 ph Alkaline water, this mitigated the problem slightly but when I would drink my urine again I would become very acidic. By day 10 I didn't want to consume anything but still drank my filtrate. Then I threw it up. This is when I decided to stop. I water fasted for the next 2 days on Alkaline Water 9.5 but was still acidic badly. I did some more research and found out a few things to be noted. Burning Keytones will cause you to become more acidic (I am overweight) Also urine being a filtrate of your blood, will contain what's in your blood. Thus although fasting, My blood was acidic. This is unique for each individual, I believe my extremely poor diet for all my life, plus excessive Drinking and Tobacco smoking played a part in why I was so acidic, during a fast your body is clearing out all these toxins that have been accumlating in your system. Point two I was following John Armstrongs anecdotal examples of him curing people with UT, he simply says in his book 2 rules Drink all urine you pass and 8 glasses of tap water a day. Of course Tap water is no longer safe to drink in most places in North America. I found a good message from some random site about UT and Urine Fasting which said "Urine is a Filtrate of the blood, if ones cells and body are toxic the blood will be toxic and thus so will the urine" it does point out that even with the toxicity, Urine will still yield positive effects but the quality of the effects will be less with unclean urine versus clean urine. Another point do not collect the the end stream of the urine maybe last couple seconds or so, this part contains stomach bile. And every Shivambu guide will tell you not to collect the first and end of your parts of your urine. I was doing this. My solution I broke my fast at 14 days and decided to spend a few weeks eating only fruits and vegetables before I try to Urine Fast again.