What to bid in this situation (xx-Kx-AQTxx-AQxx, 1D-1S-2C-2D...)? (System: Simple SAYC)
Your 2C was nonforcing; partner could have passed 2C but instead showed a preference for your first suit with 2D. This is to play. Depending on your responding style, partner could have as little as

KTxxx
xxxx
xx
xx


or as much as

KQxx
Qxx
Jxx
xxx


In any case, you don't have quite enough to take another bid and should pass. To bid again, you should have at least reversing strength (e.g.

Kx
Kx
AQTxx
AQxx


which in my opinion is not quite enough to make a game-forcing jump-shift after partner responds).