It is normal and healthy to have bowel activity frequently throughout (could even be every day) or to have no activity whatsoever for 40 days strait and neither is cause for concern.
Fluctuation in fasting weight is entirely about water. If you drink and/or metabolically create more water than you eliminate in a given period and this fluctuation outweighs the fat/protein loss in the same period, you will experience temporary gains. As a really obvious example, if you drink a liter of water in 5 or 10 minutes without urinating or sweating during that time, you will have gained about 2 pounds... and many possibilities exist for temporary gains that are more subtle.