I think its important to listen to your body. If your hands are shaking and you feel very anxious then you are way past your coffee dose!.. In my case I can only drink max 2 cups of day. So it really depends on each person.
There is no such thing as too much coffee…jk. Peter is right, but also you might want to consider other side effects like: reflux,palpitations in your heart, insomnia and dehydration.
Totally agree with all the participants. You have to check that you’re not actually drinking more than 5 cups per day, and that your body is not reacting some way to all the caffeine, because I know mine does!