Sick orchid - leaves turned yellow and dropped off after re-potting

[lemonslice27]

Hi everyone,

I recently re-potted an orchid which was doing well. The next couple days 4 to 5 of its leaves turned yellow and eventually fell off. I attached a picture where it only has two big leaves left; the yellow one fell shortly afterwards. Does anyone know what might have caused this to happen? Could something have gone wrong with my orchid mix? Should I toss it out? And how could I encourage this orchid to grow more leaves back / stay healthy?

Thanks!