If you have't got a pot put it back in the same one it was in until you get a smaller one. the 'trick'? if I can call it that is to watch the roots and make sure they get green (by saoking them) and then letting them dry.. - leaving them drier/grayer coloured for 'on more day' is better than overwatering!
Your plant actually looks very Ok to me & more than salvagable!
If a lower leaf turns yellow- that's normal it's older..
I would cut off the spent flower spike too!
I have found that Leca at the bottom of the pot helps.
Keep us posted

Hi Nenella,
so I put the orchid in a plastic container that comes with the Tide detergent (I washed it out first)It's the cup you can use for dispensing detergent. This was the only thing I had that was small and I could fit 4 of the roots comfortably without forcing them. 2 of these roots are still exposed over the medium. I also have 2 aerial roots. I left them on outside of the pot. Hubby used the drill and added lots of holes. Because the leaves on the orchid are too heavy for this container, I've put it inside another clear container (the ones you would get from the deli section - to buy olives and such) to keep it from falling over. I was even able to open the window today because it's cool out. Fingers crossed that things will work out.
Oh, I should add that I spray the root area only almost every other day.