My sister has Alz. and before Christmas her memory had gotten really bad. She was unable to remember anything after 5 seconds. I took her to visit her kids which she has 6 of them. They don't get along so she had to go to each of there houses and was moved around including a grand-daughters. When I picked her up 10 days later she was a mess. She was so drugged she couldn't stay awake and driving her home she started throwing up. She slept for 4 days. I don't know how much was from her drugs they messed up on or her depression. I haven't seen her this bad. Once she finally woke up and I am trying to get her in her regular routine. She now feels every is in the past and doesn't know what is happening to her. Why she is here, she knows she used to live here but thinks it was years ago. She is now very depressed and I'm not sure what to do for her.
Sister really needs to come to mom in the future, and ask her to stay with mom so you can get out for some respite. I would more than welcome the opportunity if offered by one of my siblings.
The confusing time with her children may have sped up her decline, but on the other hand people with dementia who don't have such a confusing week go through some of the same things. Ultimately it is her dementia which causes this behavior. Maybe she'll "heal" from those visits and get back into her old routine with you. Maybe the doctor will discover something that can be treated. Let's hope so. But it is also wise to be aware that dementia progresses, no matter what else is going on.
I agree that it might be best for your sister for her children to visit her in your home. On the other hand, you absolutely must have some respite. I hope that having her away for 10 days gave you a chance to recharge your batteries. It is awesome of you to care for her. You must also take care of yourself, and that includes having some time to yourself. I doubt that anyone can take as good care of her as you do, but you still have to have breaks.
Let us know how her condition progresses, and what the doctor finds. We care, and we learn from each other.
Beyond that, I'd just try to keep to her "old" routine with you. Have her doctor check her out if her confusion and depression continues. It might take her the 10 days to get all of the confusion and anxiety out of her system. Hugs to you both.