Okay so now I have tried to date both a girl and a guy and I just always screw up and I don't know if I really liked them as friends or if I was 'turned on'

I'm sick of not being able to say I'm bisexual or gay for three years now, I shouldn't been dealing with this by now.
Pretty sure I'm the worst human being on earth also because once I know they're onto me I treat them like trash and I don't know how to stop it ¿?