How is the class average in psychology an "F"? That doesn't make any sense. I mean, if it were actually a biopsychology class I could understand, but intro psych is about as easy as psych gets.
Anyway, assuming your college somehow managed to make intro psych hard, I wouldn't worry too much. When I took orgo 1+2 I failed every single exam; thing is, so did a lot of other people; usually the average was in "C" range. So as a result I still came out with a "B-" both semesters. I felt like I learned nothing though since the whole year was just a daze. Then I studied for the MCAT and discovered that despite having had taken orgo 3 years prior I still wasn't that rusty and it actually ended up being my best subject on the MCAT in that I killed every orgo passage I tried.
Moral of the story is that classes that are designed by your college to be exceptionally brutal can make you feel stupid even when you actually know the material very well, and you're probably better prepared for the 2015 MCAT than you think you are.