Virus ?? please help?

i have been seriously sick for about 8 days now and i went to the doctors about 5 days ago and then said it wasnt the flu and didnt prescribe me with any medicen and told me to wait it out and it should get better. Well it still isnt and i have also been told i was dehydrated and all i have been drinking his water about 5 bottles a day and the weird thing is during the day time my tempature is normal and everything and then suddenly when the night comes it shots up to about 102.5 and i cant sleep at ll and also get aches all over my legs and arms and feel very weak i also cant eat anything heavy and have to stick with light stuff , also wake up with headaches and end up sleeping with them to can anyone help to cure this ?