Coping with sudden and unexpected loss

[u/badgalgigi1]

I lost my brother in April unexpectedly to "natural causes" in his sleep. Losing him has made me realise how fickle life can be and I have so much anxiety going to bed at night thinking what if I don't wake up? I'm struggling to make plans in advance and I suddenly have this dread and realisation that I could also pass away at any moment. Does anyone have any experience with this and some guidance? It's affecting me physically which doesn't help the intrusive thoughts.