Day 1 in Before it blew up

Today is day one and I don’t know how this will go. I have always been a very out there type of person until a few years ago. I had a lot of friends throughout grade school and my family was ok. As I got to high school, I started to get into fights and people started to hate me. I ran away twice from home and was just a bad kid. Getting to junior year I started to get my shit together and made a couple friends. Met the love of my life at the beginning of 2014 and now we are getting married. My family.... well, my brother just recently got admitted to the hospital for attempted suicide and he got diagnosed with personality disorder. Including himself, there are 3 personalities in his body. My parents do not know how to deal with this type of situation so being in the medical field, I help them a bunch. My sister recently told me she is depressed and feels alone. She’s only a middle schooler so we decided to have her go to therapies which are working. I myself have had anxiety for years now and it was always self controlled until now. I find my self feeling my heart race faster than it should, I feel cold and I want to cry for no reason and my body shakes. I have no friends. My only friend is my fiancé. I feel alone but I hide my feelings to make sure my family is ok. They do not need another worry. I’m very antisocial and I do not know how to keep friendships. What do I do?