Likewise, ill-literate! I woke up with an awful stomach ache this morning (partially due to the fact that I went to bed hungry), but after sipping some iced fukamushi from the night before, I felt refreshed and ready to eat breakfast. However, sometimes when I have matcha (or the first couple infusions of a strong fuka) first thing in the morning, it can occasionally throw my tummy off. But not always!
If this regularly happens to you in the morning (and you can't eat breakfast), you can use an old fasting trick and eat a couple dates/dried apricots about 15-30 minutes beforehand. It should get your enzymes going and settle your stomach down a bit before you shower it in sencha.