My boyfriend thinks I'm pregnant, but I kept telling him no

My boyfriend thinks I'm pregnant, but I kept telling him no... Until today. So I started my period 11/10, which is when I started birth control. Had unprotected sex the the 14th and 17th. A few days later I had what I thought was breakthrough bleeding. Just really light pink, lasted maybe the whole day but I don't 100% remember, no longer than that though. My period was due 12/3. From 11/30-12/2 I had heartburn so bad it was keeping me up until 5am. On 12/1 and 12/2 I took 2 tests, one said positive for 30 seconds and faded, the other didn't even work. I decided I wasn't pregnant. I ended up being 2 or 3 days late (i even called to ask what pill I was supposed to start it on and I was already out of those ones lol), but it wasn't normal. I figured it was the new pill. I had light pink bleeding in the morning (not even 1/2 a regular tampon absorbed after 5hrs) but then barely even pink the next day. The next day I saw nothing at all. We (attempted) sex again but I started to bleed immediately (he thought) so we stopped. I went to see what was going on, and it was just a bunch of brown mucus-y discharge. I figured old blood from my period. This went on until Wednesday, when I decided to stop taking the pill as it was messing with me mentally. Then yesterday, I got period like cramps all of a sudden but only in my back, and have been having small amount of brown discharge that seemed to come and go. Today I was alright then had cramps for about 10 mins, then was alright, and am now having cramps again though in the front with a more pressured feeling, along with a large amount of bloating and gas feeling. I'm still having very small amounts of this brown discharge, but no blood, no pink/red, just brown, and mucus-y. Any thoughts?