Bad startle reflex!

Ka

My baby girl just turned 5 months and we’ve been trying to get her to sleep in her bassinet. However, whenever she falls asleep she wakes herself back up super quick. Her startle reflex goes off every 10-15 seconds, and eventually she’ll have one so big she can’t sleep anymore. There’s no noise in our room other than our ceiling fan so I’m not sure what could be setting her off? She never does this when laying with us in our bed, only when she’s by herself. Has anyone else had this problem? So far tonight she’s slept two times, both under 14 minutes because she startled herself awake 😕