It could mean a few things if you have a head ache and a stomach ache the next day after drinking. Usually the head ache could be from a hangover and the stomach ache could be from drinking too much and its unsettling. If it gets out of hand be sure to contact a health care professional.
Your body is telling you that it doesn't like all of the excess alcohol. Your brain says,"mmm, this is good", while your body says, "Stop, PLEASE!!" alcohol in excess is really bad. Alcohol is in fact, a legal drug. So, lay off the beer and wine, and give your body some resting time. (to burn it off)