but citrus is pretty acidic and can be a strong juice to deal with. Your bm & stomach discomfort may have something to do with that. If there's any way to work some veggies into your mix, it might calm your system down. A green juice in the evening is so nourishing. The fruits are great in the morning when your body is naturally cleansing itself anyway.
Sounds like you're well into your fast and it may take continued effort to help smooth out your issues.
Congratulations, you're dedicated and hopefully it will pay off for you!!!