Welcome to HW!
Depression often leads to isolation. The feelings of uselessness and sadness make you to stay away from others. But please try to be supportive for your daughter (?)! If she sees that you are worrying as well, she might feel bad for being the cause of that, which will only make things worse. Maybe you can show her your love and compassion as often as you can, be a support for her, someone who will always love her no matter what happened.
And you can never be sure. I am sorry to say that, but until you are able to read someone's mind you can never be sure. So please don't feel bad because you are not sure, it will only trigger more worry and negative thoughts. With me, I saw my parent's worrying, and thus I said I was OK when I wasn't, just to comfort them. But then my parent's took a more positive approach by not stressing anymore, but rather be a support for me. Then I felt comfortable telling them the truth.
I hope this somewhat helps, and feel free to keep on writing to us!
Have a wonderful day!
Acceptance is the key
The World is but a reflection. Smile, and it will smile back.
Try to keep smiling! :)