I received post exposure-rabies vaccine after I was bitten by a dog two months ago, now I was bitten by a dog again, should I get vaccinated again?

Depends on. I wonder if you have received antirabies Immune Globulin along with 5 doses of vaccinations. If you did not, you need to get full doses.
No. You are still covered by the last vaccine, but you should have the bite checked out for signs of infection. Also, you should reevaluate what interaction you are having with dogs that keeps getting you bit!