Amy is accusing Penny of being devastated about Leonard having a new girlfriend. Penny denies that she is.
Penny: Okay, I’m not upset about Leonard and Priya.
Amy: Your flaring nostrils indicate otherwise.
Then, as the conversation continues and Amy tries to console Sheldon about no longer being the nucleus of the group:
Amy: I’m not saying that you’re not fun. You’re the most fun person I
know.
Penny interjects:
Penny: A lot of people think I’m fun to be around.
Amy takes this as Penny needing attention and validation that she is important even though Leonard is dating someone else.
Amy: Don’t be needy, bestie. That’s probably part of what chased
Leonard away.
Then Amy and Sheldon continue to discuss how the group is now Leonard-centric:
If it were a town, it would be Leonardville. If it were an Islamic
nation, Leonardstan...
Penny than adds:
Ooh, I got one. If you guys were a band, you’d be called Leonard and
the Leonards.
Amy again takes this as Penny feeling devastated over Leonard having a new girlfriend.
Amy: So needy.