I received my first dose of the Depo-Provera shot on the 15th of Oct. My period started on the 10th of Oct and was mostly done by the 14th but I had very light spotting on the 15th (when I got the shot). I had unprotected sex with my husband on the 17th of October & everyday since. He was upset that I got the shot in the first place because he's afraid of infertility. He has been trying to get me pregnant since we got the OK from the doctor after our first born (May 2013) I'm just not ready (Ladies you know how it is!) I have had all the pregnancy symptoms INCLUDING weight gain, which I know is normal with the shot but no period, spotting or any sign of my monthly gift at all. also a side effect of the shot, however, I read it is only effective immediately if given within the first 3 days of your period & I also was on antibiotics for a cold, does this effective even the depo shot? ... could I be pregnant?