I am sorry for what you are going through. I lost my mam to lymphoma just 4 days ago and my mam's last hours will haunt me till it's my turn.  I am struggling to come to terms with it but i know it's early days and the grieving process is an ever evolving thing.  My mam made it to 80 but without a lymphoma she'd have gone on til 90 at least (as fit as a fiddle!).

It's all part of the life process. Nobody is immune to mortality. Most people feel immense sorrow and grief/bereavement at some point in their lives.  It's what makes us human beings.  Life without death would have no meaning when you think about it and a life without meaning is no life at all.  I don't think you need berevement counselling.

The ranges of emotion you describe ar a normal grieving process. It is like being hit by waves. At first the waves are big and regular with time they become smaller and in time nowhere near as often. But then out of nowhere can come a big one! And Wallop.   It's normal and believe it or not it's healthy. It means you are grieving and those are the right emotions.  I'm happy to talk anytime.