Back To 3am Feeding?!

I don't want to sound like I am complaining here, and I know there are many of you who are still waking up at odd hours of the night and early mornings to feed...But, I am finding myself up at 3am to feed Baby#1 again. Baby#1 is great, she was sleeping 12-13 hrs. a night for us, until just after she hit 4 months. Is this normal? I heard of the 4 month regression and could this be it? When will it pass-if ever?