Same thing happened to me in high school, I'm 29 now. Had no hairline sophomore year and a thinning crown.
It definitely gets easier once you get older. I remember finishing high school and doing every activity, but I didn't take a yearbook photo. That's the only thing I regret, because I couldn't accept being bald back then.
One thing that helped me in high school was finding out about toppik. It was a hugeeeee help. Probably the only reason I graduated. They are fibers that make your hairs on your head look thicker. I was able to fake having a hairline. It was a big deal to me. Made it a lot easier being in public.
