Wow, what a bummer! Generally it is good to limit new additions to 1 at a time to isolate food sensitivities. The shake can be made with a lot of different things, like almond milk (my fav), soy milk, hemp milk, coconut milk, berries, tofu. Try different things.  Same with the supplements and broth.

As far as the rash, it could be a symptom of detox or food reaction. I had a rash of sorts that I made worse by scratching and spreading. The 1st week I was itchy and a bit blotchy on back part of body and chest. It has resolved on its own.  I would say if yours gets worse, or begins to weep or produce sores, see your doctor. You might eliminate rice for a 4-5 days and see if it clears.

...one day at a time; one choice at a time...

If you don't have a problem with Vitamin C it can be a very good anti-histimine. When I've had allergic reactions it has been very good and recommended by naturopaths to take to bowel tolerance (ie, if you start to loosen up then it's time to cut it back). I was taking 3000mgs every couple of hours for THREE days before I started to get even a little loose. If I was to do that normally, I would be in the bathroom constantly, but if you are having issues your body seems to utilize the extra. Please check with someone at your local health food store that would have the right qualifications to confirm this or check it out online. It was recommended to me and worked great, but always check it out.

Definitely if it gets worse or if you notice swelling or trouble breathing, get to the hospital right away.

I would recommend cutting anything out of your diet that you believe could be the culprit.  Once the rash has cleared up you can slowly add items back into your diet one at a time to find the culprit.  I would recommend leaving 3-5 days between adding each new item.

Christina