How Can I be "Loose" When I've Only Had Sex 7 Times?

Hello Betty,
I REALLY help some advice, I'm scared I'll never be in a relationship. My problem has obliterated my self-esteem and I feel so alone.
I'm 20 years old and I have had sex with 6 different guys. It started with this one guy I liked; we had sex two separate times but he couldn't orgasm after hours of trying. I felt so embarrassed and thought he wasn't attracted to me so I freaked out stopped seeing him. After that I began having one night stands.