Freaking out!

When I went to the bathroom this small piece of tissue came out part clear and part brown. And when I wiped I could see that the mucous had a little bit of a brown tinge. I really hope I'm not miscarrying. So worried. My first pregnancy ended in a miscarriage around 9 1/2 weeks. I'm 8 weeks today. My second pregnancy was healthy and fine and I have a 2 yr old son. I would just be devastated. Has anyone else experienced this and been fine? My husband and I had sex last night could that have caused this?