she won't stop spitting up!

nae87

My DD has never been much of a spit up baby.  Recently though she's been puking up pretty much all of the meal she just ate.  It usually happens when she wakes for a feeding in the middle of the night.  She'll chug down her milk and then it all comes back up.  A few times she's choked and it came up but last night she just let it all go after I nursed her on one side.  Then she did it again in her bed.  We had to change her and the sheets.  I just got her up from a nap and she'd done it again.  She was laying in a huge wet puddle and the back of her onesie was soaked.  What is up with my baby?