Just turned 46; TTC Baby #2;possible implantation bleeding

I’m a 31 day cycle person, my hubby and I had sex right before & right after ovulation multiple times that entire fertility window. Thursday late afternoon (the day before my period was supposed to start) I got a dark brown spot on my panties a little bigger than a quarter. I went back and looked on my tracker and it’s about 12 days past ovulation. The next day (yesterday) I bled but not my usual super heavy flow & it was like pinkish red to pinkish brown in color. It wasn’t very heavy. Today when I peed and wiped I had blood but not bright red. I didn’t fill my pad & my period wasn’t heavy like it usually is the first 2-3 days. Then just now I went to pee and not a trace of blood. I showered and cleaned myself down there and not a trace of blood. On top of that I’ve been unusually nauseous in and off since yesterday. I’m convincing myself I’m NOT pregnant & that my period is just being weird. But my period has never just ended abruptly after 48 hrs. It’s literally barely been 48 hrs and it stopped. And it was nowhere near as heavy at all as normal those two days. Has anyone else here experienced this and been pregnant? I read that implantation bleeding doesn’t last long….I want to be pregnant soooo bad but I’m just not sure

UPDATE: I took a pregnancy test today and it was negative. I’m sad but staying positive….keeping the faith it will happen ♥️