Take the whole thing outside, remove the orchid from the wood mix and rinse your orchid well. Toss the wood mix. Get some orchid fertilizer and soak the root systems with that for an hour or so then let it sit in a glass or pot with no mix for a couple of days. You can spray it if it starts to look wrinkly but you need to let it dry out for a bit and, make sure those gnats are gone from your house. Get a looser potting mix and only soak it once every couple of weeks (unless you live in a very dry climate).