Lori, as Baz and Moonie have both updated to iOS 11.0.1 and there are reports that this is causing problems, that may well be the cause of what's going on.
https://www.forbes.com/sites/g...rmance/#2dbed72b5d95
http://www.zdnet.com/article/i...hone-and-ipad-users/
Advice seems to be not to update until Apple sorts out the problems.