How long halfway exactly? A lot of those big gains you may have made in the beginning are definitely from the Dbols (lots of water weight), test takes a little bit to kick in, and deca even longer I believe (please correct me if Im wrong).
As others have said, up your calories/protein. And switch up your training, if you've been doing high rep, then go low rep, with lots of sets. Well, do lots of sets anyways. 5X5, or 8X5, even 10X5