Does bleeding after unprotected sex indicate pregnancy?

Hello doctor,

I am a 20-year-old female, and I am approximately 5 feet 9 inches tall and weigh around 125 pounds. I had unprotected sex, and he pulled out well before climaxing, three days after my period ended. We had unprotected sex again after two days, but we stopped before he ejaculated due to increased sensitivity in my vagina, which caused discomfort, almost like pain. In the middle of that month, I started experiencing heavy spotting, and that night I had some of the worst pain and cramps in my abdomen that I have ever had. The next day, the pain subsided slightly, and eventually, it went away completely. However, I am still bleeding, and it is heavy enough to require the use of tampons. This has never happened to me before, so I am not sure what it is. The only symptom I have had since the pain went away is bleeding.

During these weeks, I have been eating very little and working out because I was trying to lose as much weight as possible. I know hormonal imbalance is a possibility for heavy spotting, but so are STDs (sexually transmitted diseases) and ovarian cysts. I understand that implantation bleeding usually involves a very small amount of bleeding, but I am unsure if pregnancy is even possible considering the amount of bleeding I have experienced for eight days. I plan on taking a pregnancy test once the bleeding ends, just to be safe and avoid any interference with the results. Additionally, I have a doctor's appointment scheduled, but I am starting to feel worried about the situation. I am currently taking Amoxicillin for throat irritation.

Kindly help.