Flexing the claws and stretching may accompany the rolling. As estrus progresses the female starts a strange howling that can go on for several minutes at a time. Some females spray urine in the same manner that is usually associated with tomcats - lifting the tail and squirting urine on a vertical surface. She may adopt postures suggestive of a desire to mate - tail raised, rear end elevated. A strong desire to escape the house may develop.
Some cats follow their owners around very persistently when in heat.
If your cat is exhibiting several of these signs your vet is probably right. Sadie was spayed at about 9 months old, but a few months later she went into heat. The vet performed another spay procedure two months ago, but he wasn't very optimistic because he couldn't find any remaining reproductive tissue. Poor Sadie continues to go into heat. Thanks for your help.