The "something else" wrong is most probably spider mites. English ivy grown indoors is a magnet for these critters and it is almost inevitable that the plant will become infested. Spraying the plant down in the kitchen sink when you do water will go a long way to discourage them (they hate humidity!). Otherwise, you need to obtain a proper miticide (regular insecticides have little to no effect on these creatures) and apply at 10-14 day intervals.

when is the last time you up potted ... it might be getting a bit large for that pot ...

i would probably tip it out of the pot.. and see what the roots look like.. and if they are severely wound around the edge of the pot. its probably time to repot ... in spring.. when you can do it outside... in my world ...

also.. as the plant get bigger in a small pot.. such can lead to watering issues ... and your old regimen may not work .. in other words... MAYBE it needs water a little more often because of the roots clogging the media in the pot?????

tip it out.. snap a pic.. and shove it back in the pot.. and post the pic of the roots ...

ken