Vagina feels wierd

How old are you, and how long have you been using a cup? I ask just to get an idea of how familiar you are with the texture of your period blood and vaginal walls. I don’t use a cup but have been known to explore the cavern while on my period. It’s possible you were feeling little blood clots or pieces of your uterine lining, which is normal. If you’ve been using the cup for a long time and this is notably different, you could be having a heavier period. If not, I would keep an eye on it and consider checking with your OB-GYN.