I can't say it better than all the moms that have already answered. All the suggestions are so good and do true. The only thing I would add is to watch your sugar intake (if this has been mentioned already I'm sorry). Anyway I'm 37 weeks right now with #7 and noticed that I was having major fatigue around mid morning, and I just felt like I could fall over sleeping. I decided to cut the brown sugar out of my oatmeal and have no sugar in my coffee and it made a world of difference. Just a thought.
Happy mom to 7 homeschooling kiddos.