Feeling like a jealous baby.

Im feeling worse everyday because of my parents,a quick back story, my mum and dad divorced when i was 2 ans they have not seen or spoke yo each other since, i dad is not the fatherly type , doesn't hug me or say nice things, has never supported me or even spent time with me, but i am exspeted to help him run his life and be his little wifey, clean up after him, cook for him sort out his fiances. and he is 50 years old and in perfect health, but im fine with that funnily enough because thats what i have been brought up with, i dont expect anything from him because i know i will never get anything, its my mother that causes me heartache,when my parents divorced it was very messy and i had to go live with my dad and i was lucky if i saw my mum once a week for 4 hours at my nans house (my mums mum) and thats what it was like for 14 years and some weeks i never saw her at all, then when i was 16 i moved out of my dads house, got a job and a flat and because i had my own home now i thought YESSS MY MUM CAN COME AND SEE ME and i can finally have some kind of parent who will tell e how proud she is of me and spend time with me, but oh how wrong i was, at this point she got a boyfriend with 3 kids who are older than me and she got a promotion and i saw her even less, she was too busy working or taking her boyfriends grand kids on days out or making her boyfriends sons meals and taking care of them, this is when everything took a turn for the worse, my nan (my mums mum) who i had always had a great relationship with had to have a hip operation and needed care so my mum gave up her job to care for my nan which was fine as her boyfriend had a great job and can support her, then after my nan got better my mum would go two days a week to see her and this is the part that stung me, my mum would have to drive past my house to get to my nans and for 3 years i would sit at my window waiting for her car just hoping she would stop and come and see me but she never did and it would stab me in the heart that she never once stopped to see me because she had to get home to take care of her boyfriends kids who were all 18 years old +, then fast forward a few years, im 21 now and my nan has had the beginnings of dementia, my mum now does to my nans 3 days a week and sleeps over there, and runs around after my nan like a child, my nan has become very nasty towards me in the past few years, when my nan got dementia originally in 2013 i was part of the help plan, i was supposed to stay at my nans at weekends so my mum could have a break because it would of been too much hard work for my mum to stay 3 days a week so with me doing 2 days she would only have to do 1 day but it was really really hard for me, my nan was very demanding, she would should at me and kick me out of the house and say awful things to me plus i had to work, so i had to stop going i couldn't handle it any more and of course the guilt trip from my mum has never stopped how stressed she it and how we all promised to help her but now its all down to her but i feel like she is being stupid, she goes 3 days a week, doesn't have to work, drives a flash car, takes fancy holidays to exotic lands, while i couldnrt afford driving lessons never mind a bloody car, and thats what it like now, she is now even more busy so i never see her, she always says how when my nan passes away it will all be different but i know thats rubbish, she doesn't want me, she never wanted me, my dad only wants me when he needs stuff doing, and now i feel like i need to cut her out of my life, it breaks my heart when i know i have a mother who dangles herself in front of me but i can never have her. i have told her how i feel on many occasions but i just get false promises. im sorry for rambling but i dont know where else to turn, iv asked questions on here before regarding the issues with my nan and her attention seeking and everyone was so kind and helpful so i hoped people might be able to help me again, thank you so much