need to vent!

So I've been having the weirdest month, I thought I was having a period but it started out brown and gradually went to one full day of dark/bright red blood then nothing. I have sore breasts and am so tired I've barely been out of bed for 3 days but have a negative hpt. I feel like I'm going crazy! I just want to know if I am pregnant! I could've conceived the 16th or 18th of October all the dates point to implantation. So why a negative test :(