Evening all. Bit of a long one but at my witts end

Me and my DP have a 6 month old son and have been together for just over 4 years, he is a little older than me, we moved in together 2 years ago.
MIL has always been quite overbearing, when i would travel to visit my partner in the early days when he still lived with his parents, if we would go out to a bar for drinks his mum would ask why we were going out......at 9........on a Friday night. She would actually make quite a fuss about it, if we had reservations for dinner (which was very rare) she would get quite annoyed and ask why we were wasting money on food when we could just eat what she had cooked.
Now a few examples of what has been going on in the run up to my sons birth and the months after which have been hard for me, every time i got an item of clothing or toy for my son when i was pregnant she would have a go at me, saying i was wasting my money and that other people would buy us things or that they wont fit him for long, i eventually had to hide things to avoid her having a go at me, she would even tell her friend infront of me how much "money i had wasted" which was not a lot, just H&M things, asda ect.....not exactly Gucci loafers.
When i was due to give birth, she asked DP if she could be present at the birth, he said that he thought it should be just me and him (which i was surprised about because he usually is a yes man to her) so she came to see me on an evening that she knew i would be alone and basically put the thumb screws on me saying it would be cruel to deprive DP of the emotional support he will need during my labour, as it will be hard on him aswel, i politely nodded but stuck to my guns and said no, when i did go into labour she rang the ward every hour, ofcourse they cant tell anyone anything on the phone and apparently according to the receptionist she got quite stressed and manic on the phone, we couldnt answer our phones to speak to her because there was a baby coming out of my privates obv.
I decided to BF DS and during visiting hours i was struggling to help him latch, his latch had been fine but being surrounded by people made me flap a bit, she came over, put her hand around my breast and started feeding it into my sons mouth, apparently to DP this wasnt an invasion at all, and him and his mum couldnt see why i was so shocked by it, i was actually paralyzed with absolute shock at what was happening, i couldnt believe the line that had been crossed, i wanted to cry. But the way i reacted upset MIL (all i did was put my breast away and stroke my sons head, no shouting) DP made me out to be a bitch again and i beat myself up again. Whatever.
Now she is trying to tell me what hours i should and shouldnt be working when i return to work in Feb, telling me not to buy my son xmas presents and telling me that when my family come over she wants to come to "to see them". I live far away from all of my family and friends so dont get to see them often, i just want it to be about me and my family not about me running round making drinks for MIL, my partner works 9-5 over an hour away then his evenings are filled with family meals, care work and other activities that i cant be part of because i am at home putting our son to bed, alone. (yes they go for a meal once a week, about 8 of them because family is important but he doesnt put his son to bed all week or read him a story)
Im not a mousey person but i like to avoid confrontation, mainly for my son but also because i fear sticking up for myself will leave me being the villan as usual, i dont really see a future if his mom will always have so much power over us, i dont want DS to be confused about who is the woman of our home, i want to be the powerful female figure in his life, should i leave? Am i a bitch? Im only 22 and i dont know what the eff to do for my sons future or my sanity 