I feel you girl, I’ve gone through a similar situation! MIL have a sense of entitlement but at the end of the day it’s your baby NOT HERS. Your the one who went though Labour and is their mum. Do what you think is right and try set boundaries. When my MIL acts like this I distance myself until she learns to respect how I feel! Your baby needs you and she shouldn’t be making you feel this way! My MIL constantly watches me when I’m taking care of my baby and it’s just obsessive and weird! Definitely talk to her about it or if things don’t change then distance yourself! Your feelings matter and if your not feeling ok it will only effect your baby!
For your own sanity you need to lay strict boundaries that she is NOT to come into your room, that is your safe space away from people when you are feeling anxious and you need to say that strictly to her and your partner so they respect that! Or if you can move out asap and don’t give them a spare key 🤣