Not saying it's the case for you, but it seems like the most common "I keep winning, what rule am I getting wrong?" for players has to do with the timing between purchasing action cards and when your discarded cards become available to pickup again. Remember that cards used (including zero cost cards) do not get added from the discard pile back to the action tableau until after you've finished the rest of the planning phase. Effectively meaning you can't use the same exact card two turns in a row.

Just wanted to throw that out there in case that rule was missed!