Doing Experiments on Myself

This is a lesson on how to screw up an n=1 experiment.  Oh, the perils!  How can I get anywhere without a double-blind placebo-controlled study??  Some days, I think I've got the blind part down......
Dr. Eades' latest post on restarting a low-carb diet reminded me of what happened this week.  You can see it here:  http://www.proteinpower.com/drmike/saturated-fat/tips-tricks-for-starting-or-restarting-low-carb-pt-ii/
Early this week, I gave blood.  I always take a day off from any kind of dieting on the days I give blood.  I tend to get out of whack.  Not sure why-could it be from downing the two packages of oatmeal raisin cookies, a bag of Cheetos, and a container of metallic orange juice while waiting it out at the canteen????
This canteen feast means that I always re-start my low carb diet the day after giving blood.  This time I drank more than the normal amount of water, I thought.
By Thursday, I thought I had fully recovered from both giving blood and the carb-fest.  I went out to the garden early in the day because it has been getting so hot.  The plan was to not tax myself too much or stay out too long.  As I was finishing up the the final harvesting, a friend stopped by.  So I decided to stay, and we weeded the entire herb garden, took out a couple plants, gabbed excessively and then went for turning the compost.  I think I was out there for another hour and a half or so.  Since it was to be just a short jaunt, I didn't bring any water, or stop for a hose break.
By the time we finished, I had a headache.  Then I remembered that I had gotten up too early in the morning for the real coffee, so I had fixed myself a quick cup of decaf before heading out the door.  Surely the headache was from the lack of caffeine.  As soon as I got inside, I had a cup, fixed myself a large salad for lunch, and then made a huge jar of punch.  It's just a large olive jar filled to the top with water, a plug of frozen lemon juice and pulp, and a half teaspoon of plum puree to make it pink.  I chugged the punch, yea that was good!
So I thought I had enough water with all the salad and the punch.  I didn't feel thirsty.  By the afternoon, the headache was back and I was feeling a bit weak.  I then discovered that in my rush out the door so early, I had forgotten to take my magnesium.  I took my pill with some water.  It didn't help.
Next thing, I had a snack.  Cheese.  Gotta do low carb.  That didn't help.
Next thing, I had a plum, and a glass of water.  The plums are small and I had the carbs, so why not.  That didn't help much.
Then, I kept thinking, glad this isn't happening within earshot of "coach" [redacted], for she would surely blame it all on my dangerous and disastrous low-carb diet.
Next, I downed a glass of water with some fake salt mixed in, for potassium.  I started to feel a little bit better.
I waited for a bit, and next, I downed an entire serving of full-fructose Emergen-C, with extra water, even though I knew I would pay later in extra cravings.  That didn't help much either.  Another half hour went by and I still didn't feel well.  I still had a headache and cramps in my feet.
Next, I took another magnesium pill with a cal-mag, and an extra glass of water.  Finally, that did the trick!  It was the cal-mag all along!  (Oh, and about 5 more glasses of water??)  Confounded again!  I guess we'll never know.