Mid Cycle Spotting and B6!?

Mrs.🅱️ • Mama 👦🏼 • 👼🏼 • 👼🏼 • TTC 🌈
Ive seen a few previous posts on this, but I was hoping if I put up a new one I might get some more personal insights. 
​I have been ttc since march, and my last 2 cycles I had luteal phases of 10 days. After doing some research, I stumbled across some people saying to add a vitamin b6 (100 mg) complex with vitamin c, and that it could help. So this month I tried it! 
​I have been taking it for all 19 days of my cycle now (which is normally 36 days with ovulation on cd21) and have been OPKing for the past week (no surge detected yet). 
​This morning I woke up to find a small amount of pink spotting!! Not enough to need a tampon/pad, but has been there all day, and now I'm getting cramps. I'm feeling like af is coming... 
​Does anyone think this may have been caused by the b6? Could it have been the antibiotics I just finished for bronchitis/strep? Or is it likely just a random fluke? Ovulation spotting? I'm sure there's a million possibilities, and no one knows FOR SURE, just looking for some advice. 
​I know I'm new to the ttc world, but I'm feeling slightly frustrated with not knowing what's going on.  Thanks in advance! ?