My daugter has a fever and cough what could be wrong, she is also sleeping a lot?

See her doctor. It's impossible to say without examining her, but with fever, cough, and sleeping a lot, i strongly recommend taking her to her doctor. I hope she feels better soon!
May be just cold. If you can wake her up easily she is tired from the illness. If she is difficult to wake up, not alert or responding well see the doctor immediately.
Fever with increased. This combination always raises the docotr's antennae! you child should be seen asap if she /he has lethargy with fever it may indicates neurological changes, which require evaluation for serious conditions like meningits, sepsis, etc.