Was that my period?

My fertility window was open 14-17 and on the 19th I started spotting light red only when I wipe for a few days , I had blood drop in the toilet once so I put in a tampon and it stop for my days. Now it looks like I'm just spotting light light brown. I am sick but i wake up every morning with a stomach ache and a little cramping. Should I take a test? My next period isn't due till 27 or 29.