Sick after running page

[Cari]

Dear All,

I am a 46 year old female, have been primal on and off for about 2 years, have already lost 1.5 stone (20 lb) and want to lose at least another stone, currently at approx 24% bodyfat.
My weight gain initially happened about 5 years ago due to my marriage breaking up, but I am well on track and almost back where I was before the pounds started piling on (ironically this had to do mainly with stuffing myself with too much pasta after working out, especially after running...I was carbo-loading or -replacing most of the time, you see!)

I have always been a keen runner and have done my share of half and full marathons in the past but never whilst primal. I would consider my current fitness level to be moderate, I do about 25 miles a week at the moment, usually off road in hilly terrain, some lifting and quite a bit of walking.
My pace is moderate, I'll never win a race, but I try and push myself occasionally with sprints and fartleks.
I am also not embarrassed to walk up the occasional hill.

My problem is that I have been feeling very sick after runs of over one hour recently.
This has happened in warmer weather, around 20 degrees (it never gets much hotter here!!)
I feel fine and energetic during the run and straight after, but the sickness hits about an hour after finishing.
I do have something to eat straight after the run, but try and keep it primal, nuts, seeds or olives as a snack mostly.
Sometimes I eat before, sometimes I am not hungry and don't bother.
I do take water, 3/4 litre bottle and I drink modestly before and after the run.
I don't take gels or the like.
I have read with interest the post about Noakes's new book "Waterlogged" and related posts and I definitely don't overdrink, but I am still not sure what I should be eating/drinking and when after the run to avoid feeling like this; as if I am completely dehydrated/exhausted.
This has never happened to me when eating carbs.

I am pretty worried about this as I have never experienced it before.
I love running and being out in the hills, but I hate the uncertainty wether the sickness going to "hit" me again after an enjoyable workout.

I don't want to start eating carbs, gels etc willy-nilly just for the sake of avoiding this, so any advice would be greatly appreciated.

Maybe I'm just getting old!!