Menstrual cycles have suddenly become abnormal. Why?

I apologize in advance for all the specific details.

I am a 24 year old female. My menstrual cycle is normally 26 days long. Last month I had intercourse on cycle days 10 and 18. Neither time did my husband ejaculate in me. I ended up being 3 days late for my period and it was pretty light compared to my normal flow. I got a negative result on hpts the day before I bled and on my last day of bleeding. I was experiencing pregnancy symptoms like nausea, headaches, fatigue, gas, sore breasts and even enlarged montgomery's tubercles. I'm still feeling these symptoms on and off. the bleeding only lasted 4 days (its normally 5or6)with brown spotting on the last day. I tested again 3 days later and again about a week after that. All came out negative. I have not had sex since then. If that, in fact, was a period I'd be expecting my next one in about 3 days. I've started checking my cervical position lately to try to become more in tune with my body and cycles. yesterday when I checked it I noticed it was high, off to the right, and fairly hard. It's been like that since I began checking it. (about a week ago) I also noticed when I wiped my finger off there was a pale pink shade to my cervical mucus. last night I had what I'd describe as indigestion and gas but also felt an odd pulling sensation around my belly button. These symptoms were not very painful, more of an annoyance. I woke up this morning and noticed the bleeding became heavier and turned dark red. It was watery though and did not leak into my under wear. I only saw it when I wiped. My cervix is still very high but hard. I was under the impression that it should drop low at the start of your period. If I am experiencing menstruation, this time it's 3 days early. I'm still feeling the slight pulling sensation right now. I've never been pregnant before (to my knowledge) so I do not know any thing about how it should feel.

I'm desperate to try and figure out what is going on with me. To say the least I do not feel normal. Is it possible that I was pregnant, had a miscarriage and my body's trying to go back to normal? Could I have a tubal, molar or ectopic pregnancy? Could I possibly be experiencing some weird hook effect phenomenon and be pregnant our could my hcg levels still be so low that I cant detect them and I'm experiencing breakthrough bleeding? or was I never pregnant to begin with and something else is wrong? I dont want to go to the doctor and say "yeah I think I could be pregnant but I technically havent missed a period and got 4 negative hpts."

Any insight or suggestions you may have on my situation would be greatly appreciated. Thanks.