Not pregnant

Okay ladies I need advice. I have recently come off the pill as me and my partner have decided to try for a baby, we have been having frequent sex and I haven't come on my period yet which I should of done, I have done tests and all are negative😩 I have been feeling extremely tired and back aches and sore boobs and feeling sick but at the same time having a bigger appetite. I don't know what could be wrong? Any ideas?