Blue breast veins before BFP?

Last night I noticed the dark blue veins on my breasts, going towards my nipples. I know that's a symptom of pregnancy, but I've been testing and still getting negatives. I tried the "quit trying" method last month and wasn't stressing as much, so my symptoms came as a shock to me. My question is did anyone have these BEFORE a BFP. I always thought the veins came after a BFP so I'm confused. Any input is appreciated 😊