My Grandma is Afraid to be Alone

I lived with my grandma for around 6 years now, she's 73 and has always been an independent women. Up until about 2 weeks ago she just did not want to be alone at all. I cant even go to the store, if I do she starts rocking back and forth bitting her nails and she says she can't breath. Recently her doctor changed her high blood pressure medication to cozar which she says makes her feel sick so she has not taken it in 2 weeks, she also has rheumatoid arthritis and takes medicine for that. She has been off her medication for four or five days and then restarted taking them again, could that be the reason for the scaredness?? She has an upcoming appointment but is there any advice you can give on my situation?

Thank you so much anything will help