Preganant or weird AF

I'm just looking for some opinions. My partner and I are ttc and this month af arrived on time (Sunday 10th) but only lasted 2 days (normally 5-7). Af is normally heavy and this was medium (red and brown) and by the 2nd day evening there wasn't enough to fill a tampon. From Tuesday 12th I've only had brown ewcm and only when I wipe and still have it now. I have done a pregnancy test (cheap one) which was negative on the Thursday. Since then I have been experiencing sore boobs and cramps. I guess my question is has anyone experienced this and what was the outcome? Could I be pregnant? Or could it just if been a weird period? Any advice or opinions will be much appreciated. Baby dust to you all.