False Alarm? Still a possibility?

About two weeks and a day ago I had unprotected sex. After like a week and a day i started to feel different. Nausea, dizziness, extreme fatigue, breast soreness, headaches, gas, bloating and constant urination. I had in my mind it was just too soon to be showing signs of pregnancy. But still i took a home pregnancy test which like i thought came out negative. I was supposed to start my cycle June 30th and instead had a brown discharge. I put on a pad just for protection and when i woke up I had more blood on the pad but still not alot. When I went to the restroom i had some clots and heavier bleeding with a slight cramp feeling. I took 1,000mg of tylenol and about an hour and a half i bled through a super tampon and the cramping got way worse. Medicine didn't help. I'm not sure what is going on. I felt like I was pregnant and now bleeding. can i still be? was it a false alarm?