"awake but drowsy" HELP!

The last few nights every time I put my three (almost four) month old down she has been NEARLY asleep in my arms, then the second she hits the crib mattress the flailing and attempting to roll over begins.

I TRY to not rescue her immediately. At first she silently moves around and sometimes her eyes even look like they're starting to close, but then pop pop go her eyes. And she's fully awake again.

Before the last couple days I could put her down fully or partially asleep no problem, but out of nowhere it's a problem.

HELP!!! I love my baby girl, but OMG this new nightly routine is getting REAL OLD REAL FAST!!!