How can I stop feeling so lonely?

I seriously have no friends and only 2 family members: my mom and my sister. My sister hates me and my mom is always mad at me because of my no good "attitude". I am 19 and really feel so lonely. I am not a nerd or anything but I do not know why I feel like no one cares about me at all. I got into a big fight with my mom over school but that is another story(a long one) and so i blurted out: "I want to kill myself" I do not know where it came from but I was really hopeless and mad at the same time in the car. She responded with "There are plenty of utensils in the kitchen". I guess my sister told me it was a joke later on but that made me cry all day. I could not help it but sit in my room and cry all day. I was really down and out about it all. Then my mom came in and told me this long old story of how I was thrown by my dad on the floor when i was an infant. So it was a pretty traumatic day and I do not know why I feel lonely but I do. She then told me that no one would care if I killed myself (besides herself, i ume/hope). well, maybe some encouragement will help me but other from that, I do not know much about loneliness except that i am suffering from it.