I Wiped My Vagina Like I Normally Do Going To

I wiped my vagina like I normally do going to the bathroom and I saw little black specs almost like coffee grounds on the toilet paper and I sorta freaked out. I showered and they went away but they came back today and that was 2 days ago. I have only had sex one time & it was kinda a random hookup and it was 2 months ago. I'm scared I have an std. I know I'm not pregnant though. I took the morning after pill the next day. I'm just really freaking out something is wrong with me. please give me all the information and if I need to go to the health clinic.