Need some feedback please

Ok ... so I'm 30 weeks haven't been working since I was like maybe 20 weeks because my doctor simply because I kept falling out and having contractions so that's where my current bf stepped in he is 24 he was working until he had a wreck and messed up his back so he can't work either so my grandma has been paying my bills and I hate that simply because I hate depending on anyone or asking for anything so I've been struggling but by the grace of God my bf got all the big things for the baby out the way ... ok to the point my grandma kinda sorta stays with me and she keeps my sister son who is 7 he doesn't listen, does what he wants and is bad in school and his mother she has a great job but leaves him here no food sometimes don't even bring him clothes my grandma do everything her and my grandma also speak over my head when it's obvious I'm over the apartment she don't send him food or nothing and she comes and gets him whenever she chooses to I'm so fed up I know I'm not the perfect mom but I hold my own weight and keep my child as much as I can which is a lot unless I have something important to do its so much every time I say something to her she tries to snap I'm like just take care of your son he already don't have a daddy but you wanna turn up and party and drink I'm fed up