how come I get coffee withdrawals only on a few days each month? most days I have anywhere from 0 to 2 coffees (very rarely 3) and I feel fine, it just puts me in a good mood for a while and when the effect wears off I am just kinda calm but other times I start feeling super anxious and my head hurts a few hours after consuming the coffee, is there anything in particular that causes that or is it random?
