Try recoating the sleeping bag shell with water repellent before giving up entirely on the bag. First, wash and dry the sleeping bag completely. Then apply a spray-on water repellent made for outdoor gear. Another method is to use a “wash-in” water repellent – simply add the product to the wash cycle (make sure only the sleeping bag is in the washing machine), then wash and dry the bag per the manufacturer’s instructions. That may be all it takes to restore the sleeping bag’s water resistance.