I feel like this has been done to death but...
I have had the Nexplanon implant for almost 2 years, and never really got periods on it, every 3-4 months I'd get 'old blood' discharge. But on 22nd October I had a proper fresh blood period, the first since I've had it inserted. I've been having regular sex 2 or 3 times a week without a condom since, as usual really.
I experienced a massive rise in sex drive around 31st October till about the 2nd or 3rd of November, which apparantly is common a couple of days before ovulation, and if my calculations are right I would have ovulated on or around the 5th, if it was a normal cycle of course. I did also experience some sharp pains like ovulation pain on the 7th. On the 14th I had a bit of spotting which looked like old blood. The timing and description fits for implantation bleeding. I've had mild twinges and cramps on and off in my womb area since then, although at first I assumed it may be another period.
But, there has been no period this month, it would have been due on the 19th so I'm 10 days "late". Over the last four days I have had sore breasts (never had this since getting the implant) and five days ago I had really strong nausea. I've also had intense but short lived sessions of stinging around my implant, this is new, but possibly irrelevant.
Overall, the facts point to one thing, and I do feel it...
BUT, I've only had negative pregnancy tests so far. I took one the day after my period was due (20th) and on the 23rd. Both negative, although I did think I saw a shadow on the later one, but decided I was imagining it because I had to look really hard to see it.
I'm using the HGC test strips which are meant to be sensitive (10uL/ml). But I'm not sure if they are faulty as the urine does not run evenly across the strip?
With all this in mind, considering that I'm using the implant, could I still be pregnant? What's going on here? 
