Britney Spears  nail biting car shots exclusive

Is it possible Britney's suffering from pre-engagement nerves?

We caught up with Miss Spears seriously chewing on her nails while riding in the car Monday, so we have to wonder if she stumbled upon the big news X17online reported exclusively ... that boyfriend Jason Trawick will be popping the question soon!

A source tells X17 exclusively that Jason was at Mouawad jewelers yesterday, designing the perfect engagement ring for the Princess of Pop.

Clear your schedule for summer 2012 ... I hear wedding bells!