I can't seem to please my girlfriend sexually

this may not be new to you, a friend shared similar experiences yesterday and i just thought of throwing it here and hear una view!

I've been dating this lady for 11 months and sex with her is destroying my self-esteem. No matter what I do to her and for her, I can't seem to please her or make her reach orgasm. I've used my tongue, my fingers, my p****, nothing works. Sometimes I'll go down on her and stay there for over 30 mins trying to please her and when I raise my head to see if she was enjoying it she would ask me, are you done? I strain my mouth and tongue for so long and all I get is 'are you done?' She is circumcised but I have had sex with other circumcised women who enjoyed it but this woman is just so rigid, I've never seen anything like it. But before you suggest I dump her, I need to let you know that is not an option for now, I'm crazy about her. Everything else in our relation