IMO, 5 days is the max for dry fast, especially for you, since you did not eat healthy foods before the fast.
I don't believe in preparing for fast. People prepare for the fast, then fast, then re-feed for some time with raw plant based foods or broths and then go back to normal way of eating.
Conscious eating is a training that you can go through and slowly develop your self. When you see junk foods (all packaged foods are) then think of eating plastic and tell yourself "or for me".
Break your fast after 5 days with sipping water slowly.
After you break your fast, eat only raw, organic plant based foods only.