Okay, so you are at home and friends aren't around. Get up, get dressed and go to a book store or café and sit a bit. Nothing says you have to sit at home all day. When you aren't busy is when you tend to think about him. Mia, yes, you know exactly what I'm going to say...it wasn't your job to make him happy. That was his job to do so. Happiness doesn't come from external stuff, but from within. Sure, it's nice to have those external things around you, but the bottom line is...we are only responsible for making ourselves happy. If others wish to join in whatever we are doing and/or sharing, then it's on them to do so.
What do you mean he scares you? There's no way to know what he'll do or won't do next. Bottom line, live for today, focus on today and try to find something that makes you smile for today. Leave tomorrow at the door.
Now...get out there and take a walk, sit at a café or take a drive...but do something to get yourself out of the house.
Sit quietly, the answers will reveal themselves when you least expect them to. The past is gone, the present is a gift and you need to focus on today, allow the future to reveal itself when it is ready.