Sorry to read that you and she are having to go through this.
Keep in mind she is not dead yet and may rebound while in the hospital. Pneumonia can be treated. The dysphagia (inability to swallow) can be treated in many cases and there are alternate methods of getting nutrition (although neither a P.E.G. nor a tube invading the esophagus is fun).
As to being lonely and alone, it will go by and you will start to heal. Make calls to family and friends, get outside, try to get involved in something outside your home and meet new faces and people.
Curious, Why did you let her go 5 days without real sustenance before seeking help?