Curious, do you have certain foods you like to break the fasts with? Anything you've learned you should/shouldn't do when you do break it?
Well, one thing I would AVOID is a Spicy Steak Burrito with Chili, Extra Cheese, and Ghost Peppers!
Okay, kidding aside. Some of the most knowledgeable and experienced doctors who provide medically-supervised water fasting are at the TrueNorth Health Center in Santa Rosa, CA.
While I don't have any of the clinic's literature, here's a YouTube video of a lady who does have some of their "Re-Feeding Guidelines":/youtu.be/-7vj__-hOrY
Play the video full-screen and advance to the following times to see the respective guidelines:
0:36 - The "Standard" Re-Feeding Guidelines
1:43 - The "High Sensitivity" Re-Feeding Guidelines
Generally, short fasts are usually fine for healthy people, based on what I've read. But, I'm not a medical professional. So, since you're dealing with Lyme and possibly other issues, I would suggest informing your healthcare provider(s) that you're fasting, if you've not already done so.
As the fast progresses, the less you should do. This advice may be contradictory to your energy level, but I strongly urge you to heed it. In a perfect world, all fasts would be done in an environment of complete rest and medical supervision. At the TrueNorth Health Center, they don't even allow patients to bathe or shower, as a safety measure, lest someone faint and either drown or fall and critically/fatally injure themselves.
Take it easy, take it serious, and listen to your body's feedback.
Best of luck!