What are the options for turning a bit stream into a byte stream?
I would use a frame alignment word to synchronize your data.  The basic idea is to insert your FAW at the beginning of every $N$ bytes.  After you demodulate the data you look for the FAW to synchronize the data.  To avoid false positives you should try to have a longish FAW (16 bits should be plenty) and look for repeated FAWs.  To avoid inefficient overhead you should try to make $N$ large compared to the size of the FAW.