I called in sick to work and my boss is mad at me?

I have been the past week with what could either be bronchitis or strep and today I stayed home from school since my throat felt really raw and on fire. I have a doc. appointment at 4:15 to figure out whats going on, and was scheduled to work at 5 pm. Well one of the waitresses (I work at Perkins) told me not to go in and I needed to rest. So I called in at 1:30 telling my boss I was sick. He got mad at me! I asked one of the waitresses why he was mad and its because now he doesn't have a hostess for the night shift. It was a three hour shift, and I'm really sick. Terrible cold, coughing mucus up, killer sore throat, irrating headache, and mulitple dizzy spells; I feel like the bad guy now. Does he have the right to get mad at me? I called in 3 hours before my shift.