Birthcontrol sex?


Okay so I wasn’t really sure where to post this because there’s some tmi’s. Long story short I’ve been on the depo shot for 5 years now and have never gotten a full period since then. I’ve gotten random spotting about every year but that’s it. My boyfriend and I have started having sex without condoms because I’m on birthcontrol and we’re both clean from stds. I’m worried about the effectiveness of the depo when having unprotected sex. I always get the shot the first day it’s available to be scheduled. Am I overly worrying myself or is there still a high chance I’ll get pregnant? Sorry if this sounds stupid!