Need to Vent

I just got yelled at by my mom and I don't understand why. For some context Im the middle child and Im currently looking for a job because I didn't want to attend university like my older sister did. Im still living with my mother and siblings. So today I got a call from my step mother who I have a good relationship with and she asked to talk to me,I have no idea what she wants to talk about but I'll find out tomorrow I guess. I told my mom about this because we usually tell her where we're going and with who so she knows where we are. And when my mom came back from work she just exploded at me saying I don't appreciate her being my mother and that I love my step mom more than I love her,and she threatened me that if my step mother says anything my mom doesn't like I'll be forced to move out,so basically my mom will kick me out and disown me. I told her that I don't understand why she's angry and asked her to explain but she just repeated the same thing. This has been going on since my younger sibling was born. I don't have a problem with her I got used to being ignored and stuff but I still don't understand why Im getting blamed even if I didn't do anything. My last resort was to just not say anything because at that point I really didn't have anything to say and I was just questioning my entire existence since she told me she regretted having me. It hurts really bad,I don't usually cry but this has me crying non stop for about an hour now. My older sister isn't home so I don't know what to do or who to turn to. My father isn't even in the country since he's a truck driver and now Im just scared to say anything to anyone because it'll only cause more trouble for me. So after this long and most likely not even understandable speech I want to ask if anyone has been through the same,and if yes what did you do that helped you?