What Are The Effects Of Prostap Injection While Planning A IVF?

Dear Doc, i am down for IVF treatment and i was given Prostap injection on my 21 cycle day. I was told that i will have my period as norman, but i am now 4 days overdue and don't feel like going to have my period any time soon. I am very concerned about Prostap injection as read on enternet that it is suppous to put you in to menopause??? so i am not sure why i was tol that i will have my period as normal and why would they give me this injection? Please help, would be helpful if you could breefley expalin why they give Prospan injection when planning IVF? Many thanks