I think people always associate bereavement with a death but it can be the case with any kind of loss, and yours is a big loss. You can't measure pain, so you won't know if you are suffering more or less than anyone else, and that isn't important really - the important thing is how you are feeling.
I really would try to find some time between work and kids (some counsellors work evenings) as I think you are going to need this kind of support in your journey through this loss. Yes it is a process, but it takes as long as it takes, and it isn't linear - you can experience all sorts of emotions but not in any order, but you do need to be aware of you emotions. Very often the first emotion is denial (this isn't happening) and then the other emotions like anger, sadness, etc but they vary so much.
This is much in my mind as I am seeing a grief counsellor about the death of my dearest friend at the age of 46 - eighteen years ago. I had a breakdown after her death and severe depression and on ADS and in hopsital for 3 months, but I got better and carried on with my life and never really grieved for my friend, though I missed her of course.
My friend's children are all grown now of course with families of their own and her eldest son came back from the USA with his wife and children for a month in April and this aroused all the emotions of sadness that my friend wasn't there to see her lovely granchildren. I was seeing a therapist anyway and this was on my list to talk about, and when I did, I cried all the way through. My therapist (who is lovely) said "There is a lot of raw emotion there NN" and I was flaked out for the rest of the day, but she has given me 6 more sessions to go back to the past about my friend. I cried a lot the 2nd time too, and I am tired out after (I am an old woman aged 68!!) but it;s like my grief has been bottled up.
Don't make this mistake ruby, see a counsellor or get some reading on grief - think there must a lot on Amazon. The person that springs to mind is Elizabeth Kubler-Ross who used to write on grief, but she has probably been overtaken by more up to date authors now.
You have made a good start with your book and your 5 good things, but you could use it to write down how you really feel (not for anyone else to read) I do this every day and it helps a bit, but I have always liked writing things down that are troubling me, sort of gets it out of my head onto paper.
All for now, keep us posted.