Emergency contraceptive

I had unprotected sex on Monday 20th May during my fertile window and took an emergency contraceptive pill (ellaone) the next day. For a couple of days I’ve been having weird symptoms like back pain, bloating and tummy discomfort. And yesterday i felt abit light headed🥴 .

Today i wiped after i peed and i saw very very light brown marks on the tissue. My period is coming in 7 days. What could be happening?

I dont think I usually spot before my period idk.