Or it could be what happened to my H376 hot faucet. It is a very odd design. The stem is in two parts that are screwed together. If they start unscrewing, they will cause the symptoms you describe. If so, you need to take the stem out and screw it back together. You'll need some trial and error to get it to the right length.
It may get me kicked off the site, but I found an exact replacement for the head sink faucet for my 2000 Hunter 340 for $20 at an RV parts website when Hunterowners said they were out of stock on it. And a chrome showerhead and hose to go with it.