Are the warnings and labels for energy drinks are legitimate why?

Yes they are very legit. On the back of monster energy drink it says drink no more than 3 in a 24 hour period. I drank 4 within about 12 hours, and i basicily overdosed on caffene, i started shaking, couldn't sleep for 14+ hours, heart was racing, felt like it was going to stop. PLEASE be carefull, consume responsibily