Hi, Ultra,
IMO it sounds like your DD's worries (diagnosable as anxiety/depression or not) are getting in the way of her life, to the point where you feel it affects her and the rest of your household a lot of the time.
To me, this says the sensible thing to do is to get help in working on it. Helping her learn to manage this now will be a great asset for the future; little kids have little worries, bigger kids have bigger worries, and since she seems constitutionally prone to anxiety, giving her tools to cope with it early on is a gift.
There is no shame in getting help with this.
DeeDee
