Can anyone pls give me answers ?!

I apologize if this is TMI. But I’m freaking out inside and I need answers. I took Plan B around 2 weeks ago 🤔 and I started having constant headaches with nausea, I quickly understood that those were symptoms of taking the pill. Probably 4-5 days later I decided to have sex, I couldn’t handle myself (ps I recently started having sex , the beginning of this month). Soo after having sex nothing went wrong. It wasn’t until Yesterday that I started having stomach cramps, but I ignored them thinking nothing of it , so I had sex Yesturday with my bf. He pulled out and along with my cum he seen brown stuff all over his dick..... it kind of weirded us out but I thought maybe he was to rough or went to far inside me I had no clue 🤷🏻‍♀️ so we brushed it off. But that same night I went to bed and I had serious stomach pain, with very little to no back pain. I didn’t wanna worry my boyfriend so I didn’t tell him BUT this morning I woke up and peed as usually and I had dark brown discharge. I need answers, because I’m going crazy inside. Pls help