I understand a little bit of what you're going through. I am recovering from a thyroid issue, and anemia and when I first started taking iron, I also had the racing heart and heart palpitations that you describe.
This issue is so complicated, so bear with me here....
Iron interferes in some way with thyroid medication. It's either the absorption, or the metabolism of the thyroid meds, I'm not sure. The important point is you must NOT take these two at at the same time. A few hours in between taking iron and taking thyroid meds is critical.
You must get your anemia sorted out before thyroid hormone will be effective. You're numbers are so low that, personally, I'd ask for a blood transfusion. After that you will be able to think more clearly, have enough energy to do all you need to take care of yourself. A blood transfusion will not cause heart palpitations either, but will give you some time of feeling better to begin your long road to recovery. It's really hard to take care of yourself when you feel like you're dying! Anemia is closely related to thyroid problems, and it's most likely that if you get your anemia resolved, your thyroid function will become normal.
Doctor's usually prescribe only iron supplements for anemia, but the research says that iron is not enough, especially if you have a thyroid issue. In particular, you need copper, Vitamin A and B12.
Copper is vital to the metabolism of iron. Without copper, your body cannot move the iron to the bone marrow where red blood cells are made. Iron can build up in the liver and muscles instead of increasing your red blood cells. Looking at your blood results, you have enough iron in your blood, but not enough red blood cells and very low ferritin - you need copper to move that iron around to where it needs to go. One way to confirm that your copper is low is to look at your white blood cell count. Low copper causes a low white blood cell count, particularly neutrophils will be low. Watch out for zinc supplements! Too much zinc will lower copper absorption. You need zinc, BUT, stick to 15mg of zinc a day. Zinc is added to everything these days, especially vitamins. If you're taking a few different combination vitamins, make sure zinc isn't in each one. (I had to order copper from amazon because it was impossible to find it without zinc, which was already in several of my other vitamins).
Vitamin A is also vital for red blood cell production, although the relationship to anemia is not well understood, but studies show that like copper, taking Vitamin A improves ferritin levels (and TSH). If you have a low functioning thyroid, then you are definitely deficient in vitamin A. Low thyroid causes vitamin A levels to fall because you no longer can convert betacarotene to vitamin A. You need to supplement with vitamin A palmitate from fish oil and skip betacarotene altogetherl.
B12 is important for the maturation of red blood cells. Without B12, you're red blood cells will be limp and half formed. Early symptoms are the same as for copper: heart palpitations and fatigue. Low thyroid causes absorption problems with B12. It's important to supplement with methylcobalmin sublingual tablets as the other form of B12 generally found in supplements is not well absorbed.
Midwives "prescribe" eating beef liver once a week to their pre-natal and breastfeeding patients because it is the most nutrient dense food.
I had been taking vitamin A, copper and iron, but still felt a huge improvement after eating beef liver. Don't be surprised if, during your recovery period, you see sleep pattern changes though. (After finally getting enough copper and vitamin A, I got such a huge boost of energy that I seem to only need 7 hours of sleep now - compared to my usual 9 or 10!) You're body has been working so hard to compensate for your anemia and low thyroid. You will see some ups and downs as your body begins to get what it needs.