Hon,
It doesn't matter if it is that product that bothered you, or not...you are coming to the realization that not everything is what it appears to be, or what it 'should' be...and that is truly tragic...that we disappoint youth and innocence that way.
This has been so for centuries, milleniums...ever since the first of our species discovered that they could gain advantage over others by pretending.
Still, every one of us, since the beginning, has had to come to this realization at some point...we call the realization, and our ability to cope, 'maturity'.
You have a great gift on your side. Call it intuition, or intelligence, or instinct, or whatever...you 'get it'. It is now your task to find your way, quietly and patiently, through the maze...without losing your optimism.
As for your headache, it could be caused by many things.
White potatoes, sweet peppers, tomatoes, eggplant, and tobacco, have been called members of the 'nightshade' family of plants. Many people react to them.
Some cooking pots are thought to be unsuitable for use.
The
Amalgam fillings in your teeth could be giving you difficulties.
You may be lacking any of a number of important nutrients...or you may be getting too much of something.
Begin with your instincts...your body knows what it needs, and doesn't, before your head does. Listen. And experiment, keeping to the best you know so far. And choose...always keeping open to newly-discovered possibilities.
Beware of making changes that are irreversible...until you are quite certain.
And, as you know, harm no one, including yourself.
Life is seldom fair, but it is a great adventure.
My best,
Fledgling