Margaret is correct.
But Elizabeth, you don't tell us the time of year that you are planning your Camino.
Between June and September, some pilgrims get by with just a hostel sheet.
This is a regular cotton or silk sheet folded over and sewn across the bottom and up one side.
Just crawl in when the weather is hot for a light cover. If you need a blanket and there are none, sleep in your clothes in the hostel sheet.
Me personally, I use a sleeping bag in April / May Caminos and am very happy to carry it.
David, Victoria, Canada.