After DD1's birth, Mil went into overdrive.
She was very interfering before (we had to change the locks as she had the keys just in case but was actually using them while we were at work to change the kitchen around for example, saying it was more convenient her way), but after DD's birth, she became a nightmare. She would come round 5 times a day (we live in the same village), making our 2 dogs bark like mad and wake everybody up. If the doors were locked, then she would knock and knock till the cows came home, you can all picture it.
The worst one was one day as I was sleeping while the baby was napping, I woke up to find her sitting on the corner of my bed. I don't know how she got in, but she was sitting there, with a pack of sanitary towels in her hand (I had previously said I didn't need them in an earlier conversation the same day).
Anyway, Dp said nothing to her. I was in tears, tired beyond belief, and having to accomodate HER needs was slowly killing me.
I confronted her, she said "but I only want to help", which is nice, but she couldn't understand that she needed to let me rest too. HER needs were first.
When DD2 was born, I used my poor parents as an excuse and told Mil I wouldn't invite them straight after the birth, as "last time was far too much" for me. She took the hint and said "FFFFINE!!" and walked off. She paddied for a few days, but did leave me alone (sort of).
Slowly it has all crept back up again, and the stuff she has done over the years is simply unbelievable, but that's a whole new thread.
All that to say, OP, you are not alone, and don't follow my example by not saying anything to her for years. It'll affect your mental health, and your relationship with your Dp.
Speak up.