Recently, I have been smelling something similar to urine that is nonexistent, walking through the grocery store (different grocery stores), in the pool, in the yard, one minute it is there stronger than life and the next it is gone. Today when it happened I was in the pool with my sister, she didn't smell anything. I have actually had to leave stores because the smell was so overpowering, yet no one else seemed to notice. Is this just my imagination? Should I have it checked out?