I'm not "older" but I stopped paleo efforts as soon as I found out I was pregnant. Honeynut Cheerios win every morning over the hard-boiled eggs, and my grilled chicken and broccoli doesn't taste the same now without some bbq sauce. So, I still try to be paleo-ish, but give myself a lot of lee-way.
As for your nausea, I think it's just different for everybody. I haven't been nauseous at all for weeks, and when I was, I think it was actually attributable to 1) the pre-natal vitamins, which I usually take at night, but one time I took them in the morning and vomited them up immediately thereafter, and 2) the flu, which I got right after I found out I was pregnant. It was not a fun opening to my first pregnancy. For about a week there, I thought my life was over and there was no way I could endure this for another 9 months. Thank goodness all of that went away and now I feel great-- no nausea, no vomiting, no heartburn, etc. I'd say it's genetics, but my own mother threw up for 5 months with my older brother and myself.