I urinate only at early morning 600ml, after that just 150-200 ml during the day.no infections, creatinine ok, echo ok, no edema.take 2.3l fluids dayly.drs here in brazil don't know what's wrong. any ideas?

Incomplete Data: Need more data to comment such as serum and urine osmolality, serum electrolytes etc.See a nephrologist!

Other fluid loss: I suspect you are losing fluid through mechanisms other than urination. Otherwise such a positive fluid balance and fluid retention would result in bloating and edema.

More water: You are likely not drinking enough water to replace your water loss through perspiration and respiration. Try increasing your water intake and see what happens. I am more concerned over your weakness which may sometimes result from lowering the blood pressure too much. As for the volume of urine/day, if everything ok , i won't lose sleep over it.