Removal and still no period.

So i got my nexplanon put in October 15th of 2016 taken out on May 31st of this year and I still haven’t had a period, I took a pregnancy test on the 10th of this month and no luck. It’s going on 3 months and I haven’t had a period yet, I’m not sure what to do. My s/o and I have been TTC since I got it taken out but we’re slowly giving up because we aren’t having any luck. I’ve had cramps for the past few weeks but they don’t feel like period cramps I mean some of the are stronger than the rest, I’ve been moody with everyone, having lower back pain like no other, I I’m super tired super easy. Advice?