I love milk so much but....

Can you just become lactose intolerant? I've heard that milk was the best thing for your bones and health and now studies are starting to show that it actually isn't. It's the total opposite as we aren't supposed to be drinking any other animals milk but our own. Just the other day, I was drinking it and had abdominal cramps, diarrhea, and threw up several hours later. I've been drinking milk all of my 19 years of being here. Is my body starting to reject it somehow?