XP: Baby Kick Startles self awake in crib..no sleep

bluejetta

We moved LO to crib 2 nights ago from RNP.  She is 12wks.  It has been really hard.  We have to spend 15 minutes holding her legs down once she's in the crib or else she throws her legs around and startles herself awake.  We're lucky if we get a 2.5 hour first stretch and then its up every 1 to 1.5 hours and she's not hungry etc she's just needing to get back to sleep.  This is unsustainable but we're committed to the crib and the need to get her there. Once we get to 4 months we plan to sleep train so she can learn to get back to sleep on her own when she does this, etc but in the meantime 6 weeks we are at a loss.Did anyone else find any great ways of helping baby not do this or not wake up? We are desperate.  She isn't a great sleeper to start with so I have no expectation of long stretches of sleep but my 3-4 hour stretches back would be wonderful.