Idk how to feel

Hello my name is Taylor, I'm 18 years old and found out that I was adopted two months ago. My birth mother somehow found me on Facebook and messaged me on their telling me that she was my mother. I called my mom and she told me not to worry about it and that it was probably spam. Then her and my father drove up to my college the next day to tell me the truth. When I was 13 my uncle told me that I was adopted but he was an alcoholic and my mom said that he made that up because he was drunk. I believed her and didn't think about it again. I found out that my mom other(deceased) brother was my birth father. Him and my birth mother had a troubled life and were addicted to drugs and alcohol. My birth mother even did drugs when she was pregnant with me and I was born addicted to the same drugs she was. I also found out that I have four half sisters and one full brother. I don't know how to feel or what to do. I have been feeling very alone ever since I found out. One side of me wants to get to know my birth mother and siblings but the other half knows it will kill my family if I do. I also don't want to give my birth mother the chance to hurt me again. I would really like to get to know my brother but I cant do that without also dealing with my birth mother. Any advice is very appreciated:)