yes, whenever you have reasonable cause to think that a medication is causing some problem, you should tell the doctor.
But in this case, he might not think there is a connection. Still, you never know... in the meantime, if it were me on Lasix I'd be busy replacing the minerals that the loop diuretic is eliminating through urine: especially potassium and magnesium.... and copper. Maybe they have something to do with it.
You can also cut way back on salt consumption and so need less Lasix.
Loss of appetite is common I Think. I had the same problem when using it.