Did they do a confirmation test?
Do you know what your RPR was last year? They look for a 4fold drop in your titer - with it being a 1:2 now, to have a successful treatment, it would have had to have been 1:8 or higher before.
The best way to know is to get a confirmatory test, like a FTA-ABS or TPPA, and if that's negative, it means you're negative.
Some people will always test positive with a low titer on the RPR after having syphilis. It might drop later, too.