I had an intramuscular injection of Kenalog 9/23/13 for a sinus infection and inflammation.  I, too, have always had very regular normal periods.  Not on the pill.  On 10/18, my period started as usual and was normal, except maybe a little lighter.  It stopped on 10/23, as usual. Then 10/25 i started bleeding again.  Within a day it had progressed to heavy bleeding with clots, no end in sight.  Went to ob/gyn office where they kept saying this is common at this age (42), but agreed that the abrupt change was not typical.  They reluctantly "agreed" that the Kenalog could be a contributing factor, as well as the 3 courses of antibiotics taken in August-October.  Did a pelvic ultrasound that was normal except a 4 cm cyst on the left ovary, which was not ruptured or bleeding, so not the cause of this trouble.  They suggested I take 2 Safyral (birth control pills) today, reassess tomorrow.  If bleeding continues, take two more and taper down as the bleeding slows. Has anyone else tried this and had it work?