My Dear ~ losin' it all ~
I am so sorry for your loss. No one can say that you are not allowed to feel this as deeply as you do. They are your feelings, don't apologize to anyone for having them.
Death is a hard thing, everyone handles it in their own way. Give yourself time. There is no time limit on grief. It is yours to handle as you wish.

You write well and may I suggest you do some more? Perhaps writing about this, to your cousin, to yourself, will help you sort and move through the stages of grief. Look up Elisabeth Kubler-Ross who wrote eloquently and compassionately about grief.

Many hugs to you as you allow yourself to feel this.