You may have a kink somewhere in one of the hoses, possibly even at the suction side of the pump
. disconnect the output hose from the pump
, and just use a short bit of hose from the pump to an empty bottle to check the flow. If you still have poor pressure, check the suction part of the hose, then the power supply, then possibly the pump itself is faulty. If the pressure is ok at the pump itself, you may have either a kink, or maybe just to many abrupt direction changes and/or longer runs to your faucets, or undersized hose or connections. also, check to make sure your filter or strainer isn't plugged.