Uhhh??

I've been on the pill (the one with no breaks) for over a year after coming off the implant and have never had a late or missed period on it however I'm now nearly 3 weeks late, I have missed it a few times in October but I just continued taking them as normal (it was maybe twice at most?) And have had unprotected sex. I have tested the week my period was due on 3 different days and times and tests, however all came up negative. I did have some odd symptoms like drousey Ness, feeling really nauseous and hot and cold flushes. Would it be worth testing again? Should I go to my GP just in case there's an underlying issue?