My 4 yr old unspeyed yorkie x refuses to leave a stuffed toy dog. Carries it & sleeps with it. What to do? ?

My yorkie x has taken to staying in her bed with the stuffed dog for most of the day, except for walks. She even wants to take it with her when she goes out, and refuses to leave it! She's 4 years old and I think she must be broody. Has anyone got advice as to handlling this situation - will she get over it naturally, should I have her speyed etc.? Very many thanks