AlyeskaGirl was not trying to be rude, only helpful.
Actually, I've seen many people use elipses in text and never view them as rude.
However, your curtness comes accross as rude.
You actually could have answered your own question. You already know high nitrates are not healthy for your fish, could be your gourami is showing the effects of being exposed to the nitrates for such an amount of time.
As you probably know, a series of daily water changes should bring them down.
Do you know what your
pH was before and after adding the driftwood? Driftwood can lower you pH. Fluctuations is pH aren't healthy either. However, I don't think the wood would have caused a drastic drop in pH in a little amount of time so as to effect your fish.
I've found that the liquid kits are more reliable the strips. It's less costly in the long run also.
I would question whether or not your getting an accurate nitrate reading given you're using strips.
Good luck, I hope your gourami feels better soon.