My Minpin is licking her paws constantly and acting strange

[hayleygirl]

I'm not sure if this is an allergy or something but we have recently noticed our MinPin is constantly licking the tops of her paws and is acting very strange looking at her legs like there are things crawling on them. YES we thought of fleas right away but she has been on Program for months and there are no signs of fleas anywhere. She doesn't scratch at all. She just sits and stares at her legs looking back and forth as if there is something there. She puts her nose right down as if to 'grab' at something. When she's not doing that she starts licking her paws. We have been feeding her the same food for over a year (Iams dry) and give her the same treats we always have. Could this be a behavioral thing? She has always suffered from a bit of anxiety but this behavior has only started in the last month. Nothing has changed in her environment or in the home. There doesn't seem to be anything specific that triggers this. She will start the behaviour at different times. We took her to the Vet to get checked last week and he could see nothing wrong with her. He checked for fleas and there were none. Anyone have any thoughts?