Miscarried first time, first baby :/

This morning took two pregnancy tests and both came back positive. Went to the doctor and they did blood work and urine and both came back positive. However couldn't see anything on ultrasound and had low hCG levels so they say I lost the baby. I've had no bleeding or anything but cramping. I'm so confused and sad and I have no idea how to react or what to think. Going back in two days to check up on it again for a follow up. Part of me is hoping that it isn't true.