Sex after mirena insertion

My doctor told me no sex or atleast ise back up contraception for 14 days but the mirena website said if it's inserted within the first 7 days of your cycle you don't need a back up. I got it inserted 2 days ago, 3 days after my period started, my bf & I really dont want to wait. Was anyone else told to wait? Should I listen to my Dr or Mirena? Suggestions?