Possible Solutions to Retirement Regrets
We often find that, when we retire, we miss the daily interaction with the people we used to work with, not to mention the fulfilling sense of responsibility that we get from doing something constructive.
In most areas, there are opportunities to do volunteer work, which will provide a means to fill these new holes in our lives. This is a way to get out of the house and socialize with other people while doing something constructive. If the need to make extra money is not the issue (in which case another job would be more appropriate), then volunteering is a very positive way of getting outside ourselves and "giving back" to others.
It is when we sit at home with our troubles that we stew and build things up in our minds to the point that the issues become much bigger than they really might be. I am not suggesting that we play "ostrich" and hide our heads in the sand, avoiding our problems. Instead, when there is nothing we need to do to handle our problems, we can do other things to take our minds off the problems.
My wife and I teach and tutor English as a second language (ESL) through the local library system. We do this typically two days a week. We get a lot out of the experience, and are helping immigrant folks assimilate into our culture.
There are many other opportunities to be had, with varying degrees of interaction with other people. Some folks would prefer to have less interaction, in which case, maybe boxing food to be shipped to needy people in other countries, cleaning for a person who can no longer do it for him or herself, and other such activities may be more suitable than teaching or otherwise helping out in highly interactive situations.
Also, I have had to spend significant periods as caretaker for my wife. Later, after the fact, I discovered that there are support groups and folks for caretakers. You might want to check on that. Usually, the hospital where your husband is being treated would have information about these programs, which are often run by volunteers.