Well I've heard with girls that its quite normal for some hair to fall out at different stages in life. My sisters hair started falling out regularly when she was about 18, but now she has no problems and has long really nice hair!
Anyways, your a guy, Im not sure if its normal for hair to be falling out. However, if you use gel and stuff, I suggest you cut down, as Hair gel has really bad chemicals in it, which can destroy hair cells.
Also, this may sound freshified, but try putting some oil in your hair regularly (dont go out in public with it!), just before you go to bed and wash it in the morning. Oil is supposed to be really good for your hair.
Im an 18 yr old guy myself, so I know how hard it could be, luckily it hasnt happened to me, but try not to worry about it too much.