34 weeks second pregnancy, my fundal height has decreased?

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So from the very beginning I have been measuring a week ahead, I had my OB appointment on Friday and she told me I’m a week behind now. My baby is head down, but to my knowledge I thought second babies don’t ‘drop’ until labor. My Doctor said I could have dropped a bit but didn’t tell me what station he’s at. I just didn’t know if anyone else is dealing with this or had insight.