Hey, have you considered going back to the history of your conversations and re-reading them, just to see how much you're benefiting from them and then how much she is... Like look at who gets talked about more, and if it is you, try writing her a letter, telling her you never noticed it before but her letter to you made you question, so you're writing to apologise to her, and ask if she can point it out to you if you become to self-absorbed during conversation. If she is interested in being your friend and really being a true friend, then she wont mind helping! Hope this helps!
Best of Luck...