Hello, are you worried about fasting at such low weight?
This reminds me of a video testimonial where the woman who was urine fasting talks about losing alot of weight in the first week, and then in the second week? she gained it all back. Sort of like a cleaning out of all the old stuff in the system replacing it with new clean healthy water/urine, I don't know how to describe it. Not sure about the ph tho. But from places I can't remember reading, it is said it's good also to wrap the areas that hurt in a towel with urine until morning.
Hope this helps :)
On youtube,
My 3. Day on a Urine Fast (part one)
Mónica Schütt