I'm thinking that the tiredness may have been a one-time reaction to too much magnesium. This happens to me if I take too much citrate.
Not sure about the increased anxiety--did you try tapping on it?
BTW, Magnesium oil works for some folks--you rub it on your skin. If you prefer to take it orally, you may need to try different forms, aspartate, malate, etc & see what works for you.