Kelli

Congratulations. You have taken the first steps on beating this cancer. Dental work is usually done before radiation, but fillings done after only one day of radiation sound okay to me. Heck, I had two root canals done AFTER 8 weeks of radiation with no problems. Extractions are a different story however.
Ask your doctor for a prescription for physical therapy for your shoulders and neck. I started within two weeks of my ND and it really helped. Those muscle spasms are a bitch but they should subside with therapy (another reason to get PT).
You have been dealt a hard hand here, and there is no shame in feeling depressed about it. I don't know how patients get through this TX without a caregiver. I brag a lot here about my indomitable spirit, but without the love and support of my wife, I'd have been overwhelmed. Give your self major credit for fighting for your life. As the other posters have noted, your advice to your mom is equally applicable to yourself.
You sound like a wonderful daughter,
Keep the Faith
Charm