I don't know what your breakfast drink contains, but if it has a hefty amount of calcium in it, you probably want to separate it from your Synthroid by more like three or four hours. Calcium will interfere with absorption.
I agree...eggs are great things (in moderation, of course). You can boil one, completely unattended, while you get ready, or you can hard boil them and leave them in their shells in the fridge for when you don't have time for anything fancier.
You are probably drinking it too close to your synthroid. Seperate by atleast an hour and see if there is a difference. Instant breakfat is a food replacement! Also it is full of vitamins that could be interfering the hormone. You may need to start cooking eggs!