I'm so freaking out

I have agoraphobia, and I'm getting kicked out.I'm on a welfare payment I pay my mum $100 a week to live here as my payments are fortnightly so I pay her fortnightly. My little brother on the other hand doesn't have any income my older sister only pays $50.50 a week she is 20 this year. The reason I am getting kicked out is because there are only three rooms in the house my sister has the master bedroom because she goes to uni and needs her own space as she has said multiple times. I have the next biggest room and my little brother has the smallest. My mother sleeps in the lounge room. I don't understand why I'm getting kicked out when it's my little brother threatening to kill me multiple times yes he is only 16 but my mum said if I report it I will be out on the street with no warning, all because he believes he is entitle to steal from me either money or food I buy for myself and I make a fuss of it because after rent I have only $25 each week. my brother has self harmed himself but isn't forced to go to the emergency room like I was or forced into counseling like me. I'm so afraid for my life but there is nothing I can do he has his me and slammed my head multiple times in the past but because I am 18 and he is 16 there is nothing I can do. the lowest rent in my area is $250 a week without and amenities such as gas/electric on top of that I can't afford a fridge or washing machine let alone put food in a place. my anxiety is so high rn, I can't sleep a shelter is out of the option as it is to far across the city I'm out of options.😭 I need a friend