TTC questions

My husband and I decided in May to remove my birth control (nexplanon) and TTC.. I had it removed on 5/12 - I have yet to get my cycle - but for the last 10 or so days I've experienced breast soreness mild cramping/pressure feeling and heartburn (which I never had prior)..
My period was due 5 days ago and still nothing.. I took a test a few days ago but was negative..
Any ideas?? This is my first time TTC and I have no clue what to expect.. I've never had symptoms like this before my period before!