How many weeks am I?

Met my gynae for my first prenatal appointment recently and she said based on my last menstrual period I should be about 6-7 weeks along. But when she sent me for my first ultrasound test 2 days later, the nurse who did it said that it looks like I'm about 3-4 weeks pregnant. However based on what I googled, my hCg levels were about 5-6 weeks. So how many weeks pregnant am I? I'm so confused right now. #1stimemom #firstbaby #advicepls