Does Zoloft have side effects?

For the past five years every day (especially morning) when we phone Mom, she tells us she feels awful. She never goes to breakfast at AL, only eats sweets or doesn't eat. The trouble is, we are on to her - she is quite the actress and answers every time with a very weak, phony voice, as if she is dying. Then, two minutes later, she forgets and starts talking normally. No doubt she doesn't feel good in the morning (neither do I and I'm 68!) but at 100, or even 80, I'm guessing that's normal. Our concern is she has cried wolf for 20 years so we never know if "this complaint" is real or more of the same (At her physical last week the doctor found nothing wrong with her (heart, blood tests, etc normal! He was amazed), but she is 100 so we have to consider that this can't go on forever.
Mom has been on Zoloft for about 10 days. I was wondering if it can make a person feel bad all day until their body adjusts and this is just what is happening. We had to warn AL they have to make sure she swallowed the pill because she has been known to fake it and throw it away (which of course with antidepressants can cause a problem in itself).
But this past week, she is staying to her room, even more, and not feeling well all day except to go to lunch and dinner, so I was wondering if the Zoloft has anything to do with it. I know the body takes a while to adjust to antidepressants (she is on a low dose, 25 mg) so maybe she needs a few more weeks before it starts to work? It is just impossible to tell with her, what is real, what isn't. My sister and I have joked about it for at least ten years that Mom doesn't know what a major pain or illness feels like so any little thing is a major crisis for her. Mom never gets sick or a cold, never has a headache, doesn't have any major health issues, even when she fell a couple of times - no broken bones, just a few cuts.