Mary,
I am sorry to hear your new situation. I hope I can say this right - I want this to be positive, but impersonal computers make it hard.
I have been where you are now. I'm sure others here have also. Sometimes life sucks big time and the journey is overwhelming.
Eventually it is time to consider what you will do tomorrow. Take it one day at a time. Hug the kids, talk with a friend, do lunch, whatever may be your thing. This becomes habit forming; when you are ready plan a bit further ahead.
Here it gets tricky. You want to travel, but are concerned about appointments every 3 weeks. GOOD, you are looking 3 weeks ahead already. MAKE your doctor schedule a treatment for wherever you will be in 3 weeks (Oakland?). Contact your insurance company - get them to authorize treatment wherever you will be located. Plan in advance to make your trip happen. It can be done - out of local area treatment is needed all the time. If necessary, ask your doc what would happen if you walked into an ER in a state far away from home and said, "I need a treatment ?".
If that is not working, how about you start driving a day or so after a treatment, and flying home in time for the next treatment ? (Think about travel needs)
This is for you, not about me, but I know it can be done. When your life gets turned inside-out you have to work harder to do the things you want to do. But you can do them. It does require planning ahead. Your family will understand your challenges and be supportive.
Plan to ENJOY tomorrow. Then repeat daily. It is all any of us can do.
Life keeps getting harder, but the goals and rewards are still within reach.
I wish you the very best, and I truly hope this is seen as supportive.
Best
Jack