Why haven't I had a boyfriend? I am 19 years old and i am in college! i have always had a lot of guy friends.?

my best guy friend says im a tomboy. i like sports and going to the gym. i dress nicely though, wear nice clothes, makeup and I am poised. My athletic attitude does not show when I am with my friends talking. I am a bit shy with guys I like though and I have difficulty opening up to people. I am always getting hurt with guys. They just flirt with me and give me compliments, like you have beautiful eyes or you look like this actress etc...im really annoyed cuz all of my friends who are girls have had boyfriends. i have had guys like me before, but nothing ever works out. and one guy asked me out but i did not like him i that way. please someone help meeee! like im just really worried that i will never have a boyfriend. im so scared. oh yeah i do have a tendency to deny my feelings and my friends say i am a good flirt.