When I first started LC I didn't get enough veggies and had problems with constipation too....my advice? get some Milk of Magnesia (MOM) and take an ounce of it. If you don't go within 6-8 hrs, you might want to try another 1/2 dose....but be careful since it can work too well.

Taking flax, psyllium, etc is great....but you need to make sure you drink a lot of fluids with it or they can cause their own problems.

Try taking MOM and add some more veggies to your meals.

oh yea....I've never noticed a problem with headaches from flax....but maybe it's an allergy for you?

Good luck!