Can someone please respond???

My period is lighter than usual this month. I am not pregnant, not sexually active and not stressed. The first day was basically spotting, second day was light, third day was basically “normal”, and today is the fourth day and it’s very light again. What is going on? I scheduled an appointment with a gynecologist to see what’s happening. This is the first time this is happening to me & I know my body and I am worried. Is this PCOS? Cancer? What’s going on????? Could I possibly had a cyst? Overactive thyroid?? I have no other symptoms besides a light period. I’m freaking out!!!!