When I have the flu I like to drink a warm cup of tea mixed with some lemon juice and honey.
The lemon juice and honey based tea helps me feel better when I have the flu and helps to soothe a sore throat.
Other drinks besides tea that is good to drink when you have the flu is ginger, orange juice, fruit juices etc.
You should also drink some warm chicken broth or other broths or even chicken soup which will help you get food into your system even though you don't have a good appetite with the flu.