whenever i drink coffee i fell very sleepy, why?

Really it is different from common men. Try having tea with Ginger. It is not a big issue.

What's happening when you drink the coffee is that caffeine is complicated but its main effect is to block the action of a transmitter called adenosine.So, when you block the effect then you feel more awake. Later on, when the coffee effect wears off after it gets eliminated in every 4 hours. Or the case may be, If you had a routine in which you drank coffee and then went to sleep, it may be a signal to sleep and would help you get to sleep. but mostly coffee doent atonce make you sleepy as soon as you drink it.

Coffee makes you sleepy because when consumed excessively, it promotes a constant adrenalin response, which tires the adrenal glands. Consequently, these glands are unable to make even the small quantities of adrenalin needed to help us preserve focus and concentration, which in turn creates feelings of exhaustion and malaise.

net , dont drink too much coffee at a time!!! tea is considered as sleep unenabler not coffee

Coffee has caffein but it is a drink that make you to be relaxed.

Also if you drink several cups daily you may have tolerant to caffein.

It is reported that drinking too much coffee make people addictive.

Once the caffiene starts wearing off you will experience a caffiene crash. Makes you feel very groggy.