HI Marvis,
Have you been tested for Celiac Disease? (I have it, so it's my automatic first thought hearing your symptoms, but it's a good thing to rule out). Iron anemia was one of my first early warning signs. I used to have really bad weak peely nails, frequent cold sores. thankfully no rash, but the itchy pimples could possible be dermatitis herpetiforms, which is another manifestation of Celiac. If it hasn't been ruled out already, and you are still eating gluten, talk to your doctor about testing (blood test and biopsy). Celiac symptoms can also be similar to Fibro - fatigue, aches, brain fog, the works.
If it's not that, then there could be something else preventing absorption. In the meantime, take extra of all your vitamins: C, D, B12, calcium, whatever other supplements you take. Digestive enzymes and probiotics also help. I wouldn't increase iron unless your doctor says so, but be sure to take it with vitamin C (supplement or big glass of OJ or something).
The first sign that I was absorbing nutrience properly is that my nails got so much better! Very few mouth ulcers these days too.
If it is Celiac, going gluten-free could resolve your fibro issues too, though they could be separate conditions. In any case, good luck figuring out what's up.