Help! I’m not sure if my pup is the breed I was told he was when I got him

So I got Zeus when he was 9 weeks old. The person I got him from said he was an American staffordshire terrier. However, he is 6 months now and is looking like a mix of something and I can’t tell what kind of dog he is. He is very energetic, yet loving. He weighs 58 pounds already and his back is higher than the black labs he plays with at the park. I’m thinking he might be a mix of terrier and lab, but his size is huge and he has a lot more growing to do.