Baby sleeping through the night...milk supply issue?

First, I want to say I know how lucky I am that my 9.5 week old is sleeping through the night. She's been consistently sleeping 9 hours, then eating and sleeping another 3.  Last night she went to sleep at 8pm, and it's now 7:05am and I'm still waiting for her to wake up, so that's 11 hours!  My issue is that I think it's affecting my milk supply.  Anyone have advice on when to pump to help it stay without having to wake up 3 times per night if I don't have to?