First of all, I'm so grateful for this discussion! I felt so alone till I found it.
I had my last normal period on September 9. My cycle is usually 30-31 days. I was having cramps around the time I should have gotten my period, but nothing. I did a HPT - negative. Then I started feeling nauseaus, weak, the cramps continued, I felt like something was crawling in my uterus, the feeling was so strong and unpleasant I just wanted to punch something hard! Then for about 6 days I had all the symptoms of pregnancy (headaches, moodswings, cramping, fatigue, a change in my sense of taste, watery discharge, lower back pain ...) except my breasts were not sore, just a wee bit more sensitive and seemed a little enlarged, but hardly noticably. I took two more pregnancy tests, both negative.
Then on day 36 (October 14) I got really severe lower back pain and slightly stronger cramping and then bleeding. At first I thought it might be normal pregnancy spotting (my mom had it too and really strong cramps when she carried me) but then it started getting a bit more, with clots. I felt sure it was going to be an early miscarriage and prepared myself to endure a lot of pain, but somehow it didn't come. All in all, this "period" lasted 3 days (normally 6-7), was much lighter than usual (most of the time I only needed panty liners) and was not nearly as painful as it normally is.
With it, however, most if not all of my pregnancy symptoms disappeared. The only thing that's left is fatigue, sometimes a "weird" feeling, like pressure in my womb, some nausea (but not anything like it was)...I took another home test - negative. I also keep track of my basal body temperature, and it was raised when I had the pregnancy symptoms but fell after my period came on.
I went to see my ob/gyn - didn't get further than the nurse though

who told me that I shouldn't be worried, that all this may be due to some temporary hormonal irregularities and not to worry unless I have strong pain or bleed profusely. I believed her, until I went to see my general practitioner today and explained what happened - she on the other hand told me there's a small chance I might actually still be pregnant (!) or that I might have an ectopic pregnancy (normally they don't show up on home tests). I think maybe I might even have miscarried an ectopic pregnancy? I'm also worried about cysts or PCOS...I did have a cyst the size of an egg not so long ago.
So here I am

I'll have another go at the ob/gyn this week and I'll let you know what comes out of it. I guess stressing over it isn't going to help much regulate my cycle again. I'm just feeling so confused and worried. Anyway, good luck to all of you, I hope everything will turn out all right for all of us.