We have a double sink in my bathroom. One used to always drain slow. We decided not to use it for a while. Now it's filling up with water and it's leaking underneath. Within 8 hours the pot under the sink was 75% full and there was water in the sink. Could this be a really bad clog? The water is clear though. HELP

I'm going to assume that you have the two bowls tied together with one trap. *I'm also going to assume that the bowl that's clogged is the one farthest one from the trap. Am I correct or do you have two traps?
Tell me what's leaking. (see image)
Back to you, Tom

There's water dripping drop by drop from, not sure where.I think it's above the retaining nut. We had troube with it not draining, so we decided not to use it and use the other sink in our bathroom. NO problems with that one, but the other one is filling up with water and I have a pot underneath to catch the dripping water. Within 8 hours the pot was almost full. The water drips when the sink has water in it(which we are not using that sink) when there's no water in the sink(sometimes it seems to drain itself---weird) it doesn't drip underneath. It almost looks like its' sweating under the sink, I can't tell where the water is leaking from.
HELP