Bleeding while pregnant!

Ok everyone I have been worried for two days now. Yesterday I was bleeding like a normal period. I kept checking my pad to monitor how much I'm bleeding. Well I passed a quarter size blood clot. Which is so scary! I went to the doctors today and they did a pap on me and said that my cervix is slightly open. They told me that I most likely miscarried or I'm in the process. I have been doing some googling and it's not unheard of with your second pregnancy. I'm still very scared and have been laying down a lot. Has anyone ever experienced this before? I am cramping but my bleeding isn't that heavy anymore. I also still have pregnancy symptoms. I'm waiting for my HCG levels to come back but my mind is everywhere.