I need some insight....

My period was suppose to start Tuesday May 7th. Two days before I started my period I had very light bleeding/discharge... it was brown and only when I wiped. I know it wasn’t my period because my period is usually kind of heavy and it’s pretty regular. So after I spotted that little bit AF never came. I thought I could be pregnant because I was having a lot of nausea, tender breast, fatigue... etc. took a pregnancy test 1 week after missed period (last Wednesday) and it came up positive. Every morning since I got that positive I have taken a pregnancy test and it’s been negative every time..... well today (Monday May 20th) I went to the bathroom and wiped and there is brown spotting again.... none on my panties just when I wipe. No cramps or anything.... still having symptoms of pregnancy but I’m beginning to think I’m not because all of the negative test after the positive. Surely I would have gotten a positive by now, right? Tomorrow I will be two weeks late from my period. Has anyone else experienced something similar?