My poop has been extremely watery for the past 3 years, rarely have solid poop, accompanied with a large amount of flatulence daily. Is this normal?

Not normal. Normal stools are formed. There are multiple causes for chronic diarrhea and you should see your physician soon. While you're waiting for your appointment try cutting out all lactose from your diet. This means milk, all dairy, & anything containing lactose. Lactose intolerance is the major cause of chronic diarrhea, bloating & flatulence. Avoidance for 7 days should answer the question.