Idk what to do

Me, 16 have a bedridden dad, a 23 year old sister and my mom that said she will kill me and go to jail. It all began when we went shopping and there was a misunderstanding on where we should meet after we each got what we needed to get. My mom left without a phone and when we didnt find her where we said we would meet we went onto the next stop that was ~600 meters away. My mom went back to the place we were before but my sister and dad went to the next shop. And finally, she decided to call from a strangers phone. My sister and mom had an argument about what happend but it was all left in the air while my mom went shopping alone. When we get home i find that the appointment my sister had was actually a secret date with her bf. When mom got angry about my sister leaving without a word to her i tried defending her and trying to clear up the missunderstanding but she started screaming about how i shouldnt try defending a whore and i should never raise my hand or tone against her (i pushed her hand away when she tried to punch me while she was screaming). I then tried to calm the situation by just sitting down and leting her unload. She made me say to my sister to not step foot in this house again and she left. Now i know how minor this problem is compared to what other pepole are going trough but i have a suicidal tendancies and this is the closest i have ever gotten by putting a knife to my throat. I dont want to die, but i dont want to live. Please someone tell me how to get away from this situation.