relationship advice

so, im 17 years old i 've never really been in a relationship or hooked up with a guy, its probably because ive friend zoned every guy that has ever tried to instigate a relationship with me or i completely stop talking to them altogether,i really dont know why tho.
so this summer i started hanging out with this guy(lets call him robert) who was close to my girl bestfriend, he initially told her he was interested in me and i kind off brushed it off, so one day i go to chill at roberts house and he had mike over who is my bestfriends ex, we start talking and we have a lot in commun, he then texts me to go on a date with him , after we go out robert calls me out of the blue saying how accusing me of wrongfully leading people on then being emotionally unavailable , cold and how if i continue like this ill never be in a happy relationship.
can u guys tell med why im so bad at relatioships?

Tell him to come back when he's off his period.