Depo shot and pregnancy

So I got my first depo shot in April 2014. I never got my second one. The second one would have been due in July 2014. My boyfriend and I continue to be sexually active and don't use any form of birth control. I have read that it takes nine months or longer for you to get pregnant after coming off depo. However, on my most fertile days we we active, not knowing. I am wondering if I could get pregnant? My next period is due October 24, 2014. The past few days I have been very irritable, moody, emotional, always feel sick after I eat, consistent headaches, sore breast, cramps, and diarreha (TMI). Any ideas?