Phalaenopsis hybrid yellow and fallen bottom leaves, black spots on top leaves

[keishiakei]

I got this flower from my mother in law a couple weeks ago. It said “phalaenopsis hyb” on the wrapping paper so hopefully I’m in the right section.

I’m a complete beginner at this. I have absolutely no idea what I’m doing but I’m willing to learn. I live in Norway where it’s cold and cloudy most of the time, with >85% humidity during the autumn.

She sits by the window with direct sunlight, all 6 hours of it we get up here. I water her irregularly, but never go more than 3 days without a little spray of water. Late last week I noticed her roots were drying so I gave her a lot of water until the pot is half soaked (which I realised now was a grave mistake).

I drained the water soon after I realised that the bottom leaves were turning yellow but I’m afraid it’s already too late. Now she even has black spots on the top leaf. What can I do to fix her?