Feeling Preggers, do you think I am?

I was due to have my period on Sunday. I took a preg. test last friday got a negative result. Took one again Monday after I had missed my period and it came back negative as well. Yesterday I thought I was definitely getting my period but got a small amount of brown spotting, and today as well. No red blood whatsoever. I've been having most of the clic symptoms other than the tender , but I do have white bumps around my and a blue vein (however that may have always been there). Very tired, extremely moody, got a dizzy spell today when I stood up to fast and mild back aches off and on, and I have had no morning sickness (I've never had it) but gag at certain smells. So I'm thinking that this is implantation bleeding. And I'm gonna retest Friday again. What do you guys think. This will be my third pregnancy, my first two were surprises so I never really paid attention to all this.