Please Help

For the past week or so I've been waking up and thinking about death. Not the death of myself, but the death of my loved ones, people I don't think I could live without. This has all started on a trip last month. I'm so incredibly scared of death that it wakes me up and I just can't fall back to sleep (even right now). I'm scared of being alone and not feeling ready to lose people even though I know it won't happen yet. I'm also scared of not seeing them again even though I believe in heaven and an after life. I'm just so scared by it and I don't know what to do because it's basically taken over my life through the night. It's just super sad and I'm so scared of just losing people, I'd honestly rather die first than see the people I love die. I have super bad abandonment issues because of my childhood and I think maybe that's the real cause of it. Does anyone know how I can deal with this? Did therapy help for you? Thank you.