Are these symptoms of the flu?

The flu is going around my high school and I'm worried I have it. Im pretty sure my friend has the flu and I saw her twice today, so hopefully I didn't get it. :/ I got the flu shot a couple months ago, but I sometimes still do get the flu even though I got the shot. Last time I had it was last January - though I can't remember if I threw up or not. When I came home today I felt extremely tired, even though I wasn't tired all day. I laid in my bed and could barely get up because I was so weak as well. I took a nap for around 3 hours - one more hour than I would've liked - and now I feel like throwing up, even though I woke up and drank some water (sometimes I get dehydrated when I sleep), and I'm STILL tired! I can feel myself getting a sore throat too and I have a small headache. :/ Do you think I'm getting the flu or just a plain cold, or am I just being a worrywart? Thanks!