???? please share ur experiences

okay ladies. I need some feed back on your expieriences. so I do have an 18 month old and we aren't "trying" but we are not "preventing" either. I am pretty sure I had implantation bleeding 2 1/2 weeks ago. now i am 8 days late, extremely exhausted, moody, thirsty all the time, and my boob are tingly/aching. I am getting negatives on tests. I know all women are different when it comes to HCG levels being high and low in early pregnancy. so I don't know if I'm just to early/don't have enough HCG for the tests to pick up or not. please help me! lol anybody have relatable stories?