Pregnancy and the implant

I got my implant fitted on the 12th September. So 3 and a bit weeks ago. I had sex before my implant fitting on the 15th of August. My period was meant to be due just before my implant was fitted but it never came and I also hear that sometimes the implant stops your periods. However, I was not given a pregnant before my implant was fitted and I thought that was what was meant to happen? Anyway so I haven’t had my period for a long time, even a little bit before I was given the implant. Recently I’ve been sick twice, and if I were to be pregnant I would be six weeks so sickness sounds about right by then. I’ve also had cramps in my stomach but not period style cramps and no blood. Also my boobs are suddenly very heavy. I know everyone is going to say take a test I completely understand and a will. It’s just if anyone knows anything about the situation or could help would be great. I’m quite young so it’s difficult to get hold of a test!!