Af still hasn't showed info below please help

So I just got off my implant the one in the arm on November 27th only was on it for a year after having my daughter now we are ttc again for baby number 2 anyways af hasn't showed up since the last time I had her in town and that was December 1st-4th in the middle of the month I had constant cramping and then the last few days I've had some cramps, test after test are negative and I don't know when af will show up as I wasn't regular before and would have af show up every 2 weeks so my question is why the hell is it not showing up positive? I've also been getting nauseous since 2 weeks ago is it to early to test?

How long is too long to not get a period?