Ttc after nexplanon

So I got off the rod the 31st of August i was on my period when i got it out it lasted about another 4 days then stopped i originally was using Ovia and was consist for every month till now. I was supposed to start Thursday according to that app. I downloaded glow about a week ago and input last info and they predicated for Sunday. I had sex Saturday that i was expecting to start it (usually does) but as soon as I orgasmed I had extreme pain. I have taken a test (Friday, Sunday and today with internet cheepy) and they have come up negative. I just find it weird how I’m late and haven’t been since it came out! Anyone experience this!? Could I just be still to early for a positive?

Also have a few other symptoms... but could just be symptom spotting...