Lonely

All I feel at the moment is complete and utter loneliness. I feel heart broken again and now I'm not even sure why. Perhaps it was seeing my father again, perhaps it's just life.
I want someone to hold me close and tell me everything is going to be ok, but I can't trust anyone.
Seb left such a deep mark on my heart that there is a huge part of me that feels like I can't be in that position with another person again, because it hurt so much when he died, it still eats away at me, how much I loved him, how he was going to be ok, we could have done this together, I thought the worst day of our lives was when he got diagnosed, but now I know how he must have felt, I think we could have got through it together.
I know it's only been a few years, I need time and maturity, but, how can I ever feel so strongly again? How can I trust myself like that?
But I'm so very very lonely.