This is not really clear. Is this a bottom view? Are you showing topside traces looking from the bottom? Why??
Is this a two layer board? Then the bottom layer under the circuit should be solid ground plane.
The input capacitor, C2, could be closer to the IC. Again, read the section on PCB layout in the data sheet. You might try putting a small cap from pin 10 to ground and see if that helps.
Here's another thought. Maybe try adding a resistor on the output to maintain a minimum load of a couple of milliamps.