It happened to me throughout high school. I had feelings for all my guy friends whom I'd known since primary school, but they were either spoken for or didnt see me in that way. It was painful yes, but luckly I managed to get over it.
Although one guy appeared at my college and we became close again, but he had fallen for one of my friends (ex friend now,b ut due to personal reasons) and wanted me to hook them both up. She was Jewish and her parents wanted her to see Jewish boys, so she could only have him as a friend. This upset me cause he still wanted to see her and be with her, but it was out of the question and she wasnt attracted to him anyway. Hes moved on and got himself a girl and Im over it now cause I have a wonderful guy of my own