Trust me, I know the feeling. I question what must be wrong with me all the time.
That said, Eric’s suggestion makes a lot of sense. If you are fixing a car or debugging code, the rule is always to isolate your variables and then test.
One other thought. I’ve read that most women, not necessarily 9s or 10s, are rarely concerned with one particular guy because another one will be along in 6 minutes. So, it could be the length of time between contact. A way to test this might be to take her to a number of different places on a single date, simulating multiple dates. You want her to feel as if she’s been on three or four dates with you. If she does, you should be able to see it through changes in her comfort behavior towards you at the end of the ‘excursions’.
Hope this helps!