if ur on ur 5th week, then i think its kinda late to run deca.
if u have n decanoate, it usually kicks in at wek 5th, and must be ran for 10 weeks for optimal results.
also deca must be stopped 2 weeks before test shots are discontinued, if u were to run deca inthis cycle that means thatd u have to go on this cycle for like 17 weeks. i say save it for some other cycle.