General TTC

So I’m 6dpo today. My last cycle was January 15. I am not sure if I’m ovulating late or what, but the last week I’ve felt cramps, dull and achy. Headaches off and on. Frequent nausea and heart burn (out of no where too). Twinges on both sides of my pelvis. Lower. Soooo I’ve tested twice but nothing . Not sure what to think of it. My cycle comes very regular now every 24-28 days. Various but usually shows up the third week of every month. Any thoughts? Ideas?