"Did I screw up with caveman" not really because she was playing along and kissing you back and she let you take up to your apartment. What she pulled here was ASD ( Anti-Slut Defense: The manuevers some women make to avoid taking responsibility for initiating or agreeing to sex, or in order to avoid appearing slutty to the man she's with, to her friends, to society, or herself ). Your sillly friends acted on the pretense of you and probaly messed you up and did you tell her what happen that night you passed out?
I hoped I helped you out and thanks for reading
Hey check out this website it can help you out it's a PUA Encyclopedia.
http://www.pualingo.com/