Is the water flow/pressure normal in the sink that's working?
You didn't mention the shower. Is that also not working?
When you say "no water pressure", do you mean no water at all?
If this is the first time using the pump this season, you may have air leaking into the water line on the pump intake side. That could be caused by a partially open antifreeze suction valve or by a cracked water strainer bowl on the intake side of the pump. Usually when these things happen, there's not enough suction to pump any water, but perhaps the air leak is minor and the pump can do a little.