Eva Mendes: Someone Is Following Me!

Eva Mendes got the scare of her life last night ... Someone was following her as she was driving around Hollywood.

TMZ has learned, Mendes was so freaked out, she drove into the nearest safe harbor ... a police station.

We're told cops hit the streets but couldn't find the culprit. But ... for safe measure, we're told cops escorted Eva home.

It's unclear whether it was a renegade paparazzi or a zealous fan.