I am very ill with swine flu, help please?

Well the sunday just gone , i had a very sore throat, and i started to be sick. On monday i was extremely ill and dehydrated so i had to go to the doctors. He prescribed me Tamiflu and anti sickness tablets, and yesturday i felt a lot better, and i could eat and drink normally. Today however, i have gone backwards, i have started being sick again, and i can't keep anything down. Why have i gotten worse? Thanks x