Toxic Parent?! Please Advise - NEED HELP

I just need to get this off my chest. My mother and I have a very rocky relationship. To give you some background- I had a younger brother who had muscular dystrophy who passed at the age of 13 who my mother and I single handedly took care of after her divorce from my father. My mother has always been a bread winner and I respect her for all of her struggles. But my mother has never respected me and expects me to listen and be at her side whenever she needs. She degrades me in front of people, makes it seem like I have nothing important to say, insults me, and has never taken attention to anything that pertains to my life. For example- I have a three month child and my mom is having a guest come over. She asked me to take my child over to her house for four days from 9-5 to cater to her guest. My response was well it’s silly to invite someone if you won’t be home. To which she responds- well you don’t come handy to me anyways. She calls me back the next day and obviously I’m mad so I don’t pick up her call the first time. The second time she calls - I feel bad and pick up and there she goes with the “you don’t want to keep ties with me anymore?” and all the guilt tripping. Imagine dealing with this for 28 years of your life. I feel like I’m not good enough for anything, her degrading behavior towards me has made me into this insecure, depressed person. She only sees her profit in everything, I am a married woman with a child and still I feel like I am struggling to be a good daughter for her. Oh and she constantly says my three month daughter “cries too much” so she doesn’t hold her. Just imagine. I just can’t tolerate her at all anymore because I feel like I can never be good enough. Always lacking somewhere or another. Guys is this a toxic relationship? Am I lacking somewhere? How do you deal with toxic parents? I am raising my own child and I am so scared to have her face this all.