New kind of birthcontrol

Okay so I got the implant in my arm December 23rd. And I haven't had a period since December 25th(that was the ending date of my last one) and I was just wondering if that was normal? If anyone else has had the same thing happen? I feel like I'm going to start and then it just doesn't happen. It blows :( and it makes me worry that I might be pregnant with this thing in my arm and if I was that it might harm the baby. I've probably spend $30-$40 on pregnancy test since then lol