Anyone else experience this?

AF is 4 days late but I've had very light spotting the last couple of days. Had a BFN on Friday afternoon with a blue dye test. Should I retest today with a pink dye test? Has anyone else experienced this at the start of their pregnancy or should I just wait a few more days? I cannot stop thinking about this!! No other real symptoms besides slight nausea after lunch today and fatigue midday yesterday and today. Am I just in my head with all of this? Any advice or personal experience would be appreciated!