Af wasn't Af

Lauren
Yesterday I posted that Af came. Well, it was red one time when I wiped. Then the rest of the day it was either nothing or brown. So, I figured Af was just slow to start. But, I took a test this morning and it's bfp! I'm in shock! Nervous about why I spotted yesterday though. If I have been having long cycles, could it have been implantation on cd 33? My last cycle was 37 days. I have ranged from 25-37 days in the last 6 months.