I think you need to MAKE time to see your friends and ex colleagues. The only people you seem to see are your daughter and children, son occasionally, and husband (though you hardly interact with him at all) Daughter has her working life, family, and presumably friends who she relaxes with, son too, and husband has his interests. What are your interests, and who are your companions in those interests?
Why not sit down and mark in different colours on a blank calendar the times when you are looking after grandchildren or seeing daughter, when you are doing house chores (with husband in another room) , and when you are chatting with someone you like or following a hobby or interest. I think you will find that most of it is in one of two colours.
There are so many things that you could be doing. Get a dog and take it for daily walks. You will meet other dog-owners and take it for daily walks. You will have a loyal companion and a reason to leave the house, and you could make good friends among the people you meet. Take up a creative hobby, even if you are no good at it you will have to choose the materials and design and sit down and actually have a go at making it. Join a leisure class of some kind - exercise, craft, book club, family history, politics. There will be other people there, and maybe a future lifetime friend will be there, looking for you. Go to a cafe - yes, all on your own - and sit with a cup of coffee and a scone watching the world go by.
Many of us have been at the same crossroads. You are wondering "Is this all there is?" No, there is much more, but you have to step forward to meet it. Widen your horizons!