Nexplanon and vomiting

I'm 17 and I've had nexplanon for just over a month now and since I've got it I have had unportected sex a few times. In the last few days I've had browny discharge but it has been a bit bloody too. This morning I have woken up and thrown up almost straight away which has Never happened before and I haven't even eaten anything! Is it just me getting used to the implant and hormones and having my first period on it??Or could I be pregnant?? Or am I just worrying way way too much? Some advise would be great thank you