Watchmen Goby,cloudy eyes. Help!!!

Hello,i have a concern about my fish tank and fish. My tank has been up and running with livestock for a couple months now,everyone seemed to be doing great. Everyone was eating and playing and our goby was a sifting maniac. Then about a week ago we lost our clownfish. I have done 2 water changes since setting it up,its only a thirty gallon. Now ive been trying to do water changes once every 2 weeks,but i havent done one now in a few. So i did a water cahnge the other day, All the parameters were fine,again had it double tested once by me and once my my lfs where we got the fish. Everything was fine,but after my water change my watchman goby seemed sick,lost almost all his color and both eyes were kind of clouded over,he was swimming funny and at one point was laying sideways on the sand band. We thought we were losing him :(. But then today whan i turned on the lights and fed the fish,he looked quite a bit better had more color and only one eye was clouded the other is fine. He even came out to eat. Now im just wondering was this stress related form the water change after not having one in a few weeks? Or is this an infection? And a couple of my fish do seem to have a couple white spots on them,didnt notice that until yesterday. Maybe ich?? I have no idea at this point,please help!