Greetings!
I purchase this phalaenopsis about 3 months ago from Whole Food. It was doing ok and survived the blooming time. I cut off the spikes after the flowers gone. Lately, it got a few problems.
1. It grew some on a bottom leaf and I cut it off; however the leaf on top of it seems infected by that and later it has similar spot as well. Please see attached images.

2. The leaves are very dry, not shiny at all. I try not to over water it ( once a week); whenever I watered it, one of the bottom leave would get yellowish, so I stop watering it.
How to treat the spots? Can this plant still get saved?
Why the plant is so dry yet still get yellow leaves after watering?
Should I repot it right away?
This is my first orchid. I really wish I could it keep for longer time. Any insight would be really helpful!
Thank you!