Depo Shot

On the depo shot and towards the time of getting a new one. I’m supposed to get another shot on Dec. 12 but I’m switching over to the implant. I’ve been on my period for the past 4 days but today is mainly old blood spotting, nothing crazy. I’m assuming I’m ending because it’s been about 5 hours since I’ve been awake and nothing has came. Assuming it’s ended, if I have sex within the time of getting the implant and now, can I get pregnant or is the depo still in my system protecting me?