Unfortunately I’m in the same boat with my 4 month old. He is currently going through the sleep regression and is in lighter sleep cycles longer. Sometimes I can feel him in a deep sleep and slip away for a bit or put him in his own bed, but other times he just knows right away. I’m planning on sleep training when he’s about 5-6 months as I have to go back to work then. I can give you some tips when I do go through this. She could be going through another regression and having those lighter sleep cycles as well. Leaving your shirt right next to her could help.
We do cosleep, my boy sleep next to our bed like joining bed but he have his own space, and he just have same problem lately ( he s now 1 years old ) He went to bed around 8 pm and I normally left after he sleep to clean up and he wake up like every 20 mins looking for me Been talk to my friend and joke around like or should I left my shirt with him like puppy so he think I'm next to him Well, I did try and it work he sleep better now with my shirt with him I'm thinking about shift it to comforter/snuggle now since he about the age that safe to get one
So I use a side car crib that is the same level as my bed and flush with the mattress. I nurse her to sleep while she is in the crib and, when she is sleeping, I can sneak away to use the bathroom or whatever as her crib mattress doesn’t move when I move on my bed! Also, I sometimes sleep on the floor for the same reason. When I move, I don’t move her as well, so she stays asleep! I had a shower this morning while my baby slept on the floor hahahaha
Honestly, leaving the shirt I last wore right in place of where I was laying worked wonders in the early months
Sorry no advice because I am in the same boat. Sometimes I don't get much sleep because she's restless and pulls herself to get cuddled on my right, then over to my left 😓