Can't Break Sleep Habits

I need help and I'm almost embarrassed to write this. My sweet Avery is 7 months and we still swaddle her and put her in her Rock n Play to sleep at night. She's still super comfortable with this arrangement but I feel like, obviously, she's way past the point that she should be unswaddled and in her crib. Unfortunately, the nights we've tried this have been wildly unsuccessful. We'll rock and soothe her to sleep and the second her head touches the crib mattress she screams uncontrollably and is wide awake. I've let her cry for up to 10 minutes but I am NOT comfortable with aggressive CIO and will not do that. Any advice? I'm so overwhelmed!