Period scares

Hey so I've been on the pill for a few 3 months now and it's my first time trying them. They are working great I didn't have my periods for the first 2 months to enjoy time with my boyfriend. So this week I decided to have my period for the first time using the pill. I went to the toilets and on my pad was a lump of skin like as thought it was skin from my inside of my vigina. I don't know what it was and I'm really scared. What should I do? I feel as though I should tell someone like my mum or a doctor but I'm embarrassed incase it's nothing