My story about implantation bleeding

I have always had a regular period. On November 12 I started my period and it ended November 19. Seven days after that, on November 26 I had light brown spotting for that one day, it started in the morning and had stopped by the time I went to bed that night. I thought it might be implantation bleeding, I thought it was too early but then I thought it couldn't be anything else. So I couldn't wait anymore, I bought one of those home pregnancy tests that can detect pregnancy 5 days before your missed period and it came back negative. Then I noticed on December 9 (a day before I was supposed to start my period) that my breasts were sore and then on the 10th my period didn't come and it didn't come the next day or the next day, so I bought another pregnancy test (just a regular one) and it came back positive and that is how I found out that I was pregnant.

okay, so my periods have always been on time, or at least they have for the most part, they are almost ALWAYS 28 days apart, they may be a day early or late, but no more. I have also NEVER EVER had bleeding inbetween cycles, I feel that it may be too early for implantation bleeding but I really need to know.

okay, so I was supposed to start on the 4th of November, I ended up starting on the 3rd and got off on the 9th (always 6 days) I'm 17 btw(no big deal, but the info may help) and I noticed my ovulation discharge on the 13th and 14th of November, my bf and I had unprotected sex on the 14th, (don't take birth control) so today (the 15th) I came home and I noticed that I was bleeding, the blood is somewhat heavy, but not too heavy, and it's light pink at times, and brown at times, it's a very dull brown, but it's brown nonetheless, and it's not stopping. I feel bloated, and a little sick..
what do you suppose is wrong?! please help me!