I've been to the doctors this morning and the nurse said i'm definitly pregnant because my first…

I've been to the doctors this morning and the nurse said i'm definitly pregnant because my first response tests pick up earlier then hospital strip tests. But because im bleeding she wants me to go next Tuesday for a blood test to get a more accuret result. If the blood test comes back negative i've lost the baby. She said its a 50/50 chance. She told me to rest and drink lots of fluids. Someone please give some reasurense then everything is going to be ok? Id be 4 weeks today