I'm so sorry you're feeling like this. I can tell life has been a struggle for you, and the things that have happened are going to be hard to put behind you, but there are ways you can recover. Obviously, you're never going to be able to replace some people, and I understand that this is the case. However, life goes on, and you must go on with it. Believe me, things don't get easier straight away, but people get stronger. With strength comes ease, and with ease comes happiness. One day things will be okay, you just have to wait for that day to arrive. In the mean time, try reaching out to someone like a counsellor. They can honestly help you a lot more than you might think, and I'm sure you'll feel a bit better having asked someone for help.
Take care always, and PM
me if you ever want to talk.