My 1 1/2 Year Old Short Haired 17 Lb. Dog

My 1 1/2 year old short haired 17 lb. dog licks her feet, legs, and stomach a lot. A couple of weeks ago she was obsessively licking her blanket, like she just absolutely had to do it, and was doing it as fast as she could. She finally threw up some white foam with hair in it. She hasn't done that since, but continues licking herself a lot. I don't see any sores on her. She sleeps with us, on her blanket, on top of our top sheet. She gets a bath once a week, when I wash our bedding and then hers, separately.