How do I manage living with a depressed and reclusive father?

How do I manage with a depressed and reclusive father who cannot live alone since my mother's sudden and unexpected death? I am an only daughter who moved into my parents' house (at his request) to care for him two years ago. He is 89 years old and in failing health with mobility/balance problems but refuses to accept outside assistance from "strangers" or to use a walker or cane at home. He does not leave the house except for medical appointments and he has NO outside social contacts. There have been several trips by car or by ambulance to the emergency room because he has either fallen, been ill,or threatened suicide. I'm 62 years old and have essentially put my own life on hold during this time. My father is upset if I'm not there for him 24/7 and he resents any time I might take for myself. I'm feeling really worn down mentally and physically and don't see an end to this situation in the near future. Is it time for a nursing home? ( I have Power of Attorney and would probably need to finance long-term care with a reverse mortgage.) My only sources of income are a small retirement pension from my ex-husband and one from my own employment--with the two totaling less than $1000/month.