Not myself

My mum passed away from cancer 2 months ago. I really miss talking to her, calling her or just spending time together. I feel like I took that time for granted and now I feel like part of me is gone, there is this empty feeling inside me. Last week before she passed was very difficult, she felt so much pain and I felt horrible I couldn't do anything to help. A day before she passed away she said she's dying and I was devastated I couldn't imagine the life when she's not here. The night she passed she had troubles breathing and we had to call the ambulance to go to the hospital, they gave her something to help her breath but said she won't survive the drive back home, they gave us chance to go one by one to say our goodbye as no one was sure if she'll survive the night. When it was my turn I hugged her and told her shes strong, I'll always regret not saying that I love her that night. She passed few hours after that and I still hate myself that I never said it to her. Since she passed away I've been more distant to people around me, I haven't open up about it to anyone not even my boyfriend.I'm scared to open up about it to my boyfriend but his patient and understanding, he said his there for me when I'm ready to talk. Since then I think I changed, the things that I would not mind scare me, I'm scared of losing any one else, I'm scared of being abandoned and most of all I miss her and I don't know what to do...