Ack! What should I do?!

Okay I have a couple of problems and I don't know what to do
So, from what I understand from my friend, I am being stalked by this kid in my 7th hour class.
Normally I would shrug it off BUT I just met him and he's asking for hugs and he knows what car I drive (that isn't creepy). I doubt he's trying to flirt because he's already got a girlfriend. My friend suggested that I make up an 'imaginary boyfriend'; which leads me to my next 'problem'
I really like this guy. We're friends and text eachother a LOT. Thing is I'm not sure how to tell him plus, he's my friends ex. So...what should I do? I have only talked this over with my best friend.