If it´s possible he can be catching a cricket or something you feed him with (it happens when you let the crickets in your cage).
Or it´s too hot for him up there so he is trying to cool down by visiting cold bottom.
Or he can suffer from some kind of illness (does he get enough calcium?)
Or it can be something else... I really dunno. Try to describe the cage, his food etc.
At about two months old my male veiled really started exploring his environment and this often took him to the bottom of his enclosure where he would walk aeound the floor, look into cracks and corners and occasionally "zap" a cricket.
Is yours going back up after exploring the bottom or is he hanging out down there all the time?
well, he hasn't been eating a lot lately. I think he hasn't eaten since the day before yesterday. He has been drinking and doesn't look dehydrated at all. A thing that worries me is that his feces are whiter and runnier.
Well today he ate one cricket(out of 2 that I gave him) and a fly. I think he's bored of crickets because he takes a long time to eat them, and he ate the fly as soon as I threw it in. I dust one cricket with calcium a day and one cricket with a vitamin supplement every three days. What you said about the gel around the feces is exactly the case. The weird thing is that when the poop dries up it darkens and turns brown.
Hector I think to get better help you will need to post more in depth about your husbandry.
Lighting that you use.
Cage size and type.
Temperatures:ambient and basking (if using)
How do you have the cage decorated: plants, vines, branches...etc..
Misting schedule: how long, how often
Supplements: what kinds, how often
Feeders: what do you use, what size, how much, how often
A whole number of things could be wrong. Somethings could require a trip to the vet. Some other stuff could be as easy as moving the cage around a bit. With more information I think you will be able to figure out what to do to help your chameleon out best.