"i did research before deciding on the shot. i was well aware of the weight gain and the irregular periods before going on it. i considered it to help me with the pain i get from pcos and i gotta say i don&#039;t hate it but i don&#039;t love it. it has a different effect for most females and i would definitely see a medical provider before attempting the first injection. for me, i got my period a week after the shot and i went for about a week, the second month was spotting for almost 3 weeks, the third month was spotting for 2. i went in for my second injection after being warned that the spotting is a normal occurrence as long as it is not followed by pain and that the depo doesn&#039;t work overnight. i haven&#039;t had a problem yet."