Can someone please help me stop worrying?

So I'm on the pill and I got my withdrawal bleed "period" during my placebo pills. But I'm scared because usually I see pieces of uterine lining when i do bleed and this time I only saw clots. I haven't had sex in five months yet I'm still worried something is wrong or somehow I'm pregnant. My period is ending now, and my boobs still feel kind of swollen as well when they usually don't.

Please help 😢I'm worrying myself sick