You can absolutely validate her feelings without negating yours, Crim. what Busto said is excellent advice. I had a convo with H that turned a bit accusatory in email ( you know this when the person says, " I am not angry, but..." Lol) I validated, agreed but also stated why my behaviour was that way. I acknowledged it must have been hard but also let him know that this was my view of things.
He acknowledged he was being a bit of a dickhead and explained that his head and heart basically weren't seeing eye to eye lol!
So, I think you have to throw the validation and acceptance out there and see if that is what she needs. Or does she need you to open a bit further? You can always back off a bit if not. As you said, she wasn't really hearing you anyway. My guess is you were getting a bit defensive. She doesn't necessarily want to see your side, she is telling how she feels. You just have to find a way to be good with acknowledging her feelings without swallowing the validity of yours.
For me, it's being authentic with all I say and feel.