severe constipation

Has anyone else had severe constipation the entire time they've been pregnant?!? I am 36 weeks and now also have severe hemorrhoids. I take colace twice a day, 2 fiber con pills a day, add benefiber to my water, drink literally a gallon of water (I measure) everyday, and eat NOTHING but high fiber foods, fruits, and vegetables. I went to the bathroom today and it was so big and hard that I was literally crying from the pain and my hemorrhoids are now worse than ever. I am at my wits end because I don't see what else I can possibly do. Does anyone know of anything else that might help?!! I've seen a GI specialist and she said this is pretty much all I can do. Help!!!!!!