Hi Fazzer 70. Welcome to the forum. I'm sorry to hear of your loss.
What you are describing seems very common. I used to think that people lost someone, cried for a bit, had a funeral and then carried on. When I lost my wife some people told me it wouldn't hit me till after the funeral and I thought they were mad. I was already upset how could things get worse?
Then after the funeral, as people stopped calling round, the phone calls got less frequent and I had more time to think the initial shock wore off and the reality of everything hit me like a sledgehammer. A tsunami of emotions that had me thinking I was losing my mind.
Things do get easier and keeping busy helps but the grief keeps returning often for no apparent reason. I guess it is something we have to work through at our own pace and there are no shortcuts.
Wishing you the strength to cope