Need advice

My last depo injection shot was May 17th 2016! I was supposed to go back in August but I never went I got my first period 3 Months Later In November I been trying to convince since then with no luck I didn’t have a period in March and that’s unusual so I ended up getting it in April but it was different then my regular ones and it last longer I’m on day 7 but it’s very light so idk if this is the ending of the injection if not how long does it take to get out your system or what can I take to clean it out 🤦🏾‍♀️