You're just lonely for a relationship- and you've obviously read or seen something that's mixed you up. At yr age, your hormones are raging& it's normal to worry about your sexuality. There's nothing to worry about. It doesn't mean anything one way or the other that you haven't found someone you like who likes you. You're only 17, so give yourself a break. Some people don't find someone they really like till they're in their late 20's or 30s.
If you stop worrying and start dating casually (without sex) and making friends of both genders just to go out with, eventually you will meet a boy you really like who likes you also - and things will happen naturally.
Just don't rush into anything with anyone to prove something; there's nothing for you to prove. Enjoy time with yr friends& when the time is right, romance will happen on its own.