Nexplanon period

So I have been on nexplanon since May and for some reason this month I had a super heavy period. I haven’t had a super heavy period since before I was on birth control. And even then, it wasn’t that bad. My question is, is my birth control still working since I had a random heavy period or is that normal on nexplanon. Can your periods change from month to month? I just got off of it today (day 9) and I really want to have sex with my boyfriend. I will be okay right? We are going to use a condom and he will pull out with the condom on. But there is always the chance that it breaks. Does a random heavy period on nexplanon mean it’s not working or does it really not matter as long as I can still feel my rod