You are a smart guy Timothy. You already are more than half way there realizing that serious heart related issues don't drag on for weeks, especially in an healthy 17 year old.
You are going to do just great! Of that I have no doubt. As for the eating thing, if you can just try to eat something periodically through the day, maybe soup or cheese and crackers, something healthy, even a few bites will help you maintain energy and blood sugar levels. By the way, good choice with the vitamins and supplements. I would caution you that sometimesagmesium can make you have to run to the toilet in a hurry, so don't take more than is recommended, but don't worry, if it happens it is not dangerous, just cut back a little on the amount you take. Magmesium is fantastic for helping with anxiety.
Sorry about the spelling errors, my iPhone hates me and puts silly autocorrect words where I don't want them.
Let us know how you progress.