Could I be pregnant?

My husband and I have been trying for a baby for about 4-5 months now. I got off the implanon/nexplanon implant right before we started trying. My periods aren't mostly regular. After my last cycle in June I was 3 days late for my period but eventually got it. Well this time I'm 6 days late so I took a test yesterday but it came back negative. Is it too early to tell if I'm pregnant or does that mean I'm for sure not pregnant? Any input is greatly appreciated!