Everyone varies on how long T takes to shut down the dreaded monthlies. Mine took 8 months to shut down completely, others shut down much faster. A lot of guys are on the 7 day cycle, myself included. It does keep things a bit steadier if you can handle getting poked in the butt (or spot of choice) every week.
After only two months on T though, you may just be experiencing the normal battle of the hormones and it might not be related to time between shots.
Dennis