We Are Ttc, Just Started. 2 Days Before My Period

We are ttc, just started. 2 days before my period I had spotting (very odd for me without birth control ) and then suppose to have my period yesterday and had started but it didn't last more 6 hours and light. Took a pregnancy test bc it was gone same day and I always have my period about 4 days with the first day moderately heavy. The test was negative. I'm so confused! Just turned 37, never irregular without birth control. Excessive tiredness, irritable, and confused what is happening.