People come into our lives for a reason, a season, or a lifetime. (Can't remember who first said that, but it is so very true.)
Life as you knew it no longer exists. You have a beautiful baby to care for and a beautiful life to look forward to. It's all up to you to put things into motion, and you can do it! You can pray for your friends and give them to God, and then ask God to send new friends into your life. Friends who are healthy and good for you and your child.
Are there some places you can go during the day to escape your house and your dad where you can meet new friends? Can you do some volunteering? Go for walks or hang out at the park with your baby? Meet with other moms and their kids?
I'm sorry you lost your friend in such a horrible way. Please take care of yourself...and remember that you have friends here who care about you.