could your lo be having a growth spurt?? that could account for the hunger.
i have been expressing milk on and off throughout my ds five and a half months and my milk does seem watery sometimes but not others, i don't think that it has coincided with my babe being extra hungry. it is supposed to be more like skimmed milk at first, like a thirst quencher, and the milk at the back is fattier. i don't think you should worry about your milk if bf has gone well up to now. breasts will produce on demand and re absorb what is not needed, it sounds like yours are doing a great job to me......!!!!
thats just my two penneth, i hope it helps!!!