HCG level going low

J

Last week Tuesday my HCG level froze being high to low and on Friday I saw my doctor he sent me to do an ultrasound and they couldn’t find a baby’s heartbeat. And later on my doctor called me and said that I am going to have miscarriage. So since Friday till now I am not feeling like I am pregnant I am only having terrible migraines. No bleeding or anything at all. Right now I am just confused this is my first pregnancy and I don’t really know how the whole miscarriage works. Please I need you help please I am so confused right now and very worried.