Just had normal mri/mra of neck, carotid, posterior fossa - now numbness face, then arm, now legs. should i worry about stroke?

No: Not stroke. Have you had any EMG or other testing? Is c spine ok?!

Neurologist: .If these symptoms persist you should have an evaluation by a neurologist to check for polyneuritis, multiple sclerosis, calcium deficiency, etc. Stroke wouldn't affect such scattered areas of the body.

Yes: If you just had clear imaging recently, and then after that started noticing this, then yes, you should still consider stroke. While those images came out clear, that was just one moment of time. Anything can happen after that, and with one sided numbness, i would recommend getting checked out as soon as possible.