In times of stress and angst, my mother always prescribed a deep calming breath and a Nice Cup of Tea. In times of big stress and angst, however, too many of those Nice Cups of Tea can send your over-caffeinated nerves a-jangling and tank your coping skills all the more.
So, how much caffeine is in a cup of regular black tea?
In part, it depends on how strongly your tea is brewed, how many tea bags or spoonfuls of tea laves in relation to how much water, and how long you let it steep before drinking.
(My grandmother used to let tea stew on the back of the stove for half the day, adding another splash of water or handful of tea leaves from time to time so the pot never ran dry. Her tea could bring a strong man to his knees.)