Sick from green juice

Hello all,

I just started a juice fast (feast) yesterday and plan to go for about 10 days. My problem is that I can't drink anything near the recommended amount (4litres) and I can't abide anything with greens. I feel sick and actually threw up after drinking them. The taste doesn't bother me but it sort of churns my stomach. I really want to continue but I'm wondering if this isn't too much for me. I did a Master cleanse several years ago and liver flushes after that but I don't have the time right now and thought this might be a bit easier.

Could this be a detox reaction? I am drinking a lot of water but I can't think of anything else to do.

Thanks in advance.