You def don't need to use diuretics to be flat, not that I am saying you are. Overall you looked great. One thing is for sure from looking at those pics, you did something to effect your sodium and potassium balance. Even though you had a little bit more fat to lose that had noting to do with what happened to you. I am going to take a guess and say that you cut your water too early and probably did a modified "shit load" hours before the show.
alot of guys come in out of shape and think it's a water issue.
they'll take their diuretic with the logic that it'll magically sharpen them up, and then use like you said a shit load to pull any sub-q water they imagine is blurring their lines.
but becuase they weren't in shape to begin with instead of ending up sharp and skin tight, they end up looking worse than if they had just not taken anything and had gotten on stage with just 5 coats of protan and nothing else.
the truth is they just weren't in shape. in pics in thier front yard or the lighting in their house they look sharp, but once they get under stage lights it's a whole different ball game as they expose every flaw and lack of detail.
this is what happened to TP- lack of disciplene in his prep. he can sing spill, flat or whatever but the truth is he was not in shape.