Seriously freaking out about Breakspear my job at a grocery store

So I've been working at this grocery store(won't give a name) that's owned by a big chain of grocery stores in California.

When I started there, they told me some information about breaks which I promptly forgot. Lunch is scheduled, so I know when to do that, but 10 minute breaks are not. I've been working here for 4 weeks or so(was officially working there but had to wait a week for training) and I haven't been taking 10 minute breaks. It's not that the store refuses to let me, it's just that I really don't know whether I'm supposed to log them on the machine or not. I figured it wasn't a problem because nobody said anything about it, but my pay stubs have a small amount of overtime each week which I assume comes from the breaks I haven't been taking.

I'm seriously freaked out that they're going to find out so I don't want to bring it up. I figure I'm on some kinda probation period and that this might put me in a tiny bit of jeopardy, but they haven't noticed.

I've been trying to discreetly check on my coworkers to figure out if they log in and out for breaks on the machine, and I will check the stub today as well as take a break after this lunch. Can anyone ease my paranoia?