We had a disruption in water service yesterday. The water is back on but my bathroom sink upstairs us now coming out at a trickle. Everything else seems to have normal pressure but that sink. The water company says that it's not their problem since the water IS back on. So what's the deal and what do I do? Please note that this is an old house built in the 50's and I have no idea about the plumbing. There's no shut off for the sink that I can see. The water company mentioned something about a pressure regulator but I have no idea what they're talking about.