How can I (32M) make sense of my wife’s (28F) shifting comments regarding sex?

TLDR: wife gives different answers on sex demanding on her mood, can’t improve based on it

I'm trying to have better sex with my wife but she constantly changes her story and it’s hard to keep up. I have had some success taking about sex outside of it, like what works and what doesn’t.  I’m not really sure the motivation and not sure if other women have done the same. 

She will say things like “oh babe not too deep that hurts” or “you’re stabbing my uterus” then I brought it up later about how I’d try to not go so deep and she is like “you weren’t touching my cervix”

Then she mentions she’s shallow, I’m a “good fit for her” and I cause her pain sometimes going too deep (I’m very average) and then a couple days later she goes “I’m normal depth and the pain is because I’m not turned on or we’re disconnected”

It goes outside of pain too. She one time said we had the “best sex ever” and even brought it up a week later, then a month afterwards she was like “I don’t remember saying that.” It’s kind of weird honestly and I can’t put my finger on it.