Suggest Medicine For Headache, Upset Stomach And Weakness

I have a headache, upset stomach and chills and no energy. I didn t feel well yesterday but felt worse this morning. I m a little better now. . I don t know if I might have the flu. I did have a flu shot. I m a 65 year old woman. I don t think I have a fever but am going to get a thermometer. I m wondering what medicine to take for my headache and for these other symptoms. Thank you.