Poor pump pressure

Our water pump seems to be giving us almost no pressure. I can get it to pour very lightly out of the faucets and dribble through the toilets, but it doesn't even have enough pressure to send water through the shower, much less actually use it.

With the rig now winterized, I won't get to it until spring, but is is safe to assume that the pump is dying and needs to be replaced, or are there other issues that should be looked at before I replace it?