Period 5 days early?

I have been pretty regular since weaning off from nursing a few months back. This month we BD 3/16 & 3/17. My peak opk was 3/17. Estimated ovulation date was 3/18. Period should be due around 4/2. Well today I started spotting a rusty color with EWCM. This has never happened in the past. I have zero other symptoms. I know our periods can change but has anyone experienced this before and got a positive pregnancy test? Should I test and if so when?