YANBU. I had a friend who did this. Always fitting me in with meetings, or asking me to travel long distances to have a coffee somewhere which was convenient to her, and after a year or two of this when I tried to redress the balance and asked her, for the very first time, to come over to where I was, she resisted and squirmed and very reluctantly agreed only after I said I can't make it then. After that she would never meet me halfway, I always had to go to her. What made it worse, was when we would have a quick coffee, she'd tell me how the night before or that evening she was off out to do something nice with another friend. I'd sit and listen and look at her in disbelief, feeling pretty sick inside. Whenever I asked her to do anything similar, she always said she didn't have time.
Finally, she messed me around three times in a row, and the third occasion big time, mucking up my summer holidays, then called me to tell me what a great time she had with friends who were on the visit she had asked me to go on months to keep her company before and then never arranged. It was really the last straw. I went NC, probably not the best way, but I could not take any more.
Her husband got in contact a year later, said he was with her and asked how I was. I told him how hurt I had been and why I had gone NC. He would have passed this on, I thought she might get in contact and apologise. She didn't. In fact I can see her fuming that someone dared rebelled!
She's not a horrible person, just selfish and obviously my friendship didn't mean a lot to her. That realisation is where I got to, and I decided not to waste my time and friendship on her any more. I feel freed up from constant imbalance which just wears you down.
If you feel you can tell her, do. Otherwise just step back - your time and friendship is as precious as hers to give, remember that.