Desperate for help

This is going to be long but idk what else to do. My periods for the past 20 years were always very heavy and lasted 7 days and I got severe cramping on the first day. They were always on time without fail. For almost two years now my SO and I have been TTC. This October I had my period regularly and during ovulation we had sex. 10dpo and a week before my period was due I had weird bleeding that lasted 3 and a half days. It was light spotting but with blood clots. I thought it could be implantation bleeding. I took a test but it was negative. I waited to see if I would get my actual period but I didn't so I tested again with negative results. I went to see my OBGYN and she tested me but still negative. She said it was probably just a weird period. So I left it alone. So that means I got two periods in October. I decided to wait for my next period in November. That period did not show up so I tested again with negative results. I ended up getting an ultrasound at my OBGYN but they didn't find anything. Ever since October though I have been having weird symptoms. They are Fatigue, headache, cramps (sharp sometimes and sometimes achy) decreased appetite, light headed ness, bloated, acne, frequent urination, get cold easily, night sweats I think, moody, emotional, nausea (mostly at night) back pain, sensitive nipples. Could it be something else or could it be by some miracle that I am pregnant? Sorry for the long post but I would really appreciate any help.