So I had my nexplanon in since I was 15 at the end of November. It lasted up to 3years. I'm now 18 and my birth control expired. I have to wait to get it removed. The boy I'm sexually active with , we don't use condoms. But my period is a week late now. I had a regular period in October and November. Is it just my birth control messing with me or is it a possibility that I'm pregnant? Please help!