Best answer for whether or not you're dehydrated... get yourself a specific gravity meter and check exactly how concentrated your urine is. Readings above 1.010 indicate relative dehydration. I am using one from Instant Ocean... had to buy it off eBay tho, b/c our local pet store didn't stock one that was closed at the bottom. You can read more at the Water Cure
click on "Hydration Meter"
You'll find this info...
urine should be at 1.010, ideally btwn 1.004 and 1.008
Specific gravity between 1.002 and 1.035 on a random sample should be considered normal if kidney function is normal. *Since the sp gr of the glomerular filtrate in Bowman's space ranges from 1.007 to 1.010, any measurement below this range indicates hydration and any measurement above it indicates relative dehydration.*
If sp gr is not > 1.022 after a 12 hour period without food or water, renal concentrating ability is impaired and the patient either has generalized renal impairment or nephrogenic diabetes insipidus. In end-stage renal disease, sp gr tends to become 1.007 to 1.010.
Any urine having a specific gravity over 1.035 is either contaminated, contains very high levels of glucose, or... (experienced an intravenous drug application)