Help me please what do i do??do i tell him im in love with him? PLEASE HELP?

ok so i am a freshman in high school there's this guy in my lab cl we used to just like talk and stuff, we work on our labs together (we dont have to we just do) and i guess between all tht i fell for him when i told my friends they were not suprised at all they all said it was obvious....i flirt with him all the time and he still doesn't get the messege...my friend said she thinks he likes me too because like he always does little stuff for me (not big stuff like he will let me copy his labs but no else, sometimes i don't feel like sharpening my pencil he will just do it for me lol) and she also said i always see the way he looks at you when you are not looking..........the problem is i think he likes another girl i always see them walking down the hall and yesterday i saw him walking her to the bus....but she also has a boyfriend......my friend thinks i should tell him that i like him but im scared because if i do and he doesn't like me back it will be akward between us????? and also do u think he likes me what are these mixed up signs hes giving me?? btw....lab is the only cl i have with him and thats the only place where i can talk to him........also if u think i should tell him how do i do it?? what do i say?