I don't drink coffee or use any stimulants but once i took a 200mg caffeine pill and it made me sleep after 20 minutes of taking it, is that normal??

Hard to say: but people with paradoxical reactions to stimulants may have one of the conditions that are specifically treatable with stimulants, such as attention deficit hyperactivity disorder (ADHD), narcolepsy or a shift disturbance disorder. You need a physician with expertise in sleep disorders to take a full history, perform an appropriate physical examination, and do whatever ancillary tests are needed.