why is my protein shake making me sick?

I am almost 10 mos out and  I never did the protein, I couldn't stand the taste and then I realized they made me sick, nausea and just stomache. I realized the whey does have milk and as I've gotten older milk is a problem for me, so that was an issue. then I tried soy protein and it just tastes bad. so no protein powders for me. I do eat the zone perfect protein bars, finally found some I actually like, fudge graham and chocolate cluster, pretty good, I had bought many many and they tasted like cardboard. and yes, my iron is low and so is everything else, probably cause I didn't do the powders and i'm not faithful with my vitamins, so if you can find something you can tolerate then take it. I had to edit this to add that the regular size protein bars I can only do 1/2 at a time cause of the sugar, I don't do sugar. but I just recently found a box of the bars in snack size! perfect!