I had a huge allergic reaction from a bee sting so the urgent care Dr. prescribed a Kenalog shot. I thought that if it would reduce my huge arm it sounded good. Well, not so good as others who have had the shot have described. I am so happy to read the side affects of others because I was starting to think that there was something serious was going on with me. I started mt period after a week after my previous one and have had this period for seven days. I usually only have five day periods and have been very regular. I called my obgyn and they said that the pharmacist stated that this is not a side affect of Kenalog. This is obviously not true and the medical professionals should be aware of this awful side affect. I have also had a dull headache for a week which has also worried me. I guess I will try to wait it out. How long does this crazy shot stay in your system?