What's wrong with me (I feel extremely worthless)?

for the past two years i haven't done much of anything. I had a job but got fired a few months ago. i feel alone even when i'm with friends. i can't get close to people because i fear they will not like who i truly am. i feel like i can't do anything and so i don't even try. whenever i try to do even household chores my grandmother laughs at me if i fold a shirt wrong and if i try to cook anything she takes the spoon away from me, tells me i don't know what i'm doing, then she asks me why i "don't do anything." my mom nags me about not having a boyfriend and tells me she's "still waiting for a grandchild." she seriously wants me to get pregnant out of wedlock because she doesn't think i'll do anything else for myself in this life. she says she'd rather have me at home than at school, and whenever i do get money saved up she takes it for cigarettes. i feel so stupid and incapable of the simplest things, i feel like i'm just here on earth sucking up everyone else's air and for that i should just do everyone a favor and die. i'm 20 years old and have been applying to different jobs to atleast move out, so before you say things like "you chose your life" and blah blah blah...trust me if i could move up, i would. i feel terrible for having to depend on my mom still, and that adds to my guilt.