anxiety about my grandmother's health

I have had anxiety since childhood. In May of last year, my 86 year old grandmother who adopted me suddenly had some type of confused or demented episode where she had delusions and out of control behavior that was not at all like her. Then, in January it happened again. I'm not sure what caused it, lack of sleep, reaction to medication, or the fact that we have had 5 deaths in the family in the last year and a half. It was extremely traumatic for me to see her this way, and I felt totally helpless. She was hospitalized and was put on medication for her heart (high BP) and also Seroquel, which can be dangerous for the elderly. We live together, and I am constantly worried about her, watching over her to see if she has side effects or any other strange behavior. I don't have family who live close enough to help me, and I also have a fear of driving. I don't leave the house unless we need groceries, medicine or have dr. visits. My grandmother seems better; she has calmed down and can do several things she needs to, but I can't stop worrying all day. She tells me to go do something for myself, but all I have to comfort me is my computer. I don't feel like I can leave her alone for very long. So, we sit in the house and she watches tv. I try to control what she eats (low salt) and the things she does (watching & reading about bad news) because I think I'm trying to help, but instead it causes arguments. She hates being watched and tells me she feels ok, but now she is worried about me, because my hands shake and I cry alot. I worry about not only her health, but also my future. I'm 37 and haven't worked in several years since caring for my grandmother. I am applying for disability for my anxiety and also some physical problems. A doctor gave me a prescription for Buspar but I'm afraid to try it because I don't want to be too sedated to help my grandma if something happens.

Any advice is appreciated.