my molly is swimming weird... doing circles.?

so, I have a black molly that I treated for pop-eye a few weeks ago. it seemed to be doing fine up until last night, I noticed it swimming all hectic and doing circles and just looks like its about to die. even when it had pop eye it wasn't doing this.. it just sat on the bottom, so i am wondering if there's anything I can do to try and save it one last time.... should I get it away from my other fish and treat them with the pop-eye stuff again?