35 weeks feeling so tired

So I am 35 weeks and I feel very tired and sleepy! I had my first at 37 weeks. I don't feel any pressure at all down there and I feel like my baby is sitting high. My lower stomach also feels like it is empty. But my doctors told me the baby's head is down so I am really confused. Does anyone else feel like their lower stomach is empty? Every where else on my belly feels really hard like I have Braxton hicks all the time.