implantation bleeding? HELP!

Ashley

Hello! my husband and I began trying to conceive. We started on May 8th (my period was due on May 11th) knowing that the chances of getting pregnant right before your period is impossible. My cycles are also irregular at times. Well May 8th came and went with no period, I began getting hopeful that I was pregnant and my periods came back negative. When I was five days late for my period, my doctor gave me a blood test. which also came back negative. 7 days after my missed period, I began spotting lightly and I got excited that it could be implantation. It was really spotty and light for the first 3 days, at times it was even nonexistent. I began bleeding a little heavier on day 4 (just barely enough to fill a small tampon, which is still very abnormal for me bc I have heavier periods). Then in day five it was spotting lightly again and today (day 6)I have brown discharge (which I have never experienced before). Could I be pregnant? I hope so but I keep reading that implantation only lasts for up to 3 days and anything after that is a period. plus there was that one day where it was a little heavier than spotting! help!