I really appreciate if any1 can answer this:-D

I am 23yrs old. My last normal period was on October 2012 which I actually got twice for that month. At 1st of Oct and later on 27 of Oct. Well the 27 Oct was pretty weird because it came a bit early and I have been having cramping which is unusual for me. But the flow was normal with heavy flow and clots. I have been having sex in between the periods.

I was late for the next period for about 3 weeks and I have took HPT and it all come back negative. But later I started my "period" on 10 Dec 2012 but it was only spotting red/brown with CM. Nothing much only needed a liner. This continue for 2 weeks until I get light period(red blood but no clots which i usually had) which only require a pad a day. I usually need more than 4 normally. This go on for a week. After that it was spotting until the "period" finish. I have been to the doc when I am spotting and she just said I was stress out..Maybe I am. 

But now after a week later, the spotting come back like I first did in early Dec. Its been 3 days now. They usually show at the evening. Same as the last time. Took another HPT yesterday it is negative. And no sex since october. So can anyone tell me whats wrong? 

Also not in any BC pills.

Thanks!