Sleeping through the night... Pumping?

Melissa
My 2 month old started sleeping from 10pm-6am the past two nights. She would normally wake up at 3am, so i never had to set an alarm because she would wake up at that same time for me to feed her. Now that she's sleeping until 6am, I wake up and my breasts are so engorged and painful. Should I start setting an alarm and waking up in the middle of the night to pump? My fear is that if I do that, and this is just a fluke that she is sleeping so much, she's gonna start waking up at 3 again and I won't have any milk because I just pumped. Any advice on what other mommas do?