I believe that thyroid hormones change because of what and how much we eat.Low iron and stress do effect my thyroid hormones.So sorry you are going through this

I had brain fog and cognitive issues terribly that spanned for months. I was extremely upset because I needed to interview for a new job and thought how in the world am I going to learn new things?! My therapist recommend a supplement called Ashwagandha Root. Gaia is the brand I use comes in 60 liquid phyto-caps which you take 2x a day. I went from forgetful, not recollecting word/phrases to remembering and having intelligent fog free conversations again. I find this at my local hippie health food store. It's also sold at Whole Foods and online. Stick to this regimen twice a day and you should notice results. It's wonderful! Good luck xx

I don't think you've suffered brain damage. I was pretty hypothyroid before I discovered what the problem was back in March. My doctor prescribed me natural desiccated thyroid and we've fine-tuned the dose over the past few months. My brain fog has lifted and I'm feeling a lot better in all respects.
I think hypothyroidism simply slows down your metabolism a lot. Think of an animal in hibernation. They don't suffer brain damage, yet their metabolism slows down a lot more than ours did when hypothyroid. Go easy on yourself. The more you worry about memory, the worse it'll be to recall things.

Ralpert, I experienced almost losing a job because of the brain fog, short-term memory loss resulting in not being able to keep up with the standards.

One solution that has really, Really worked for me is --and you're not going to believe this is --BREATHING EXERCISES. Yes, Breathing. Breathing brings oxygenated blood to ALL parts of the body. By breathing thru your nose it travels very fast. The day that I discovered this, I did it all day long and felt a difference, definitely by the third day. I also failed in school because of these symptoms and had to drop the program. This REALLY WORKS--to get rid of migraines, muscle cramps, depression, nauseousness, relaxation, anxiety. In the beginning I did the exercise all day and now I do it 5 times a day or more.

Dr. Andrew Weil-Tutorial 4-7-8
https://www.youtube.com/watch?v=_Wg-UAYGa2A

Ralpert, another solution, have ALL your hormones checked, insist on this. I say this because this cleared up part of the problem. I learned ALL hormones work together and pretty much RUN the body including the brain; the brain is nothing without hormone. Once I got on progesterone, estrogen and testosterone, I no longer need Levo or Armour. Research the symptoms when the levels are low.

Another thing I had going on was ADRENAL FATIGUE which mimics hypothyrodism, hashimoto. I have CHRONIC STRESS so I re-live the symptoms. I had 3 doctors helping me. I bought the hormones from a Compounding Pharmacy so the pharmacist there wanted to treat me and gave me powerful vitamins, NOT a medical drug. I learned that vitamins B & C are depleted during CHRONIC stress so These powerful vitamins re-store my health many times over. I can cut back when there is less stress and during chronic stress I can increase the dose but they work wonders. I strongly recommend to research Adrenal Fatigue. Dr. James Wilson also has a website and also has a questionnaire that you might like to take. The vitamins seem to work like a medical drug for me because contain so many that we need. I had fallen apart, I could barely function after a chronic stressful episode, it took 2 hours to me back together; this is how powerful these are.

For me, ALL of this works together.

I also invested in Sea Kelp supplements, which have Iodine, it feels like they clear up the brain fog, I feel a clearer mind and add energy so I take it no later than 2 p.m. You could invest in kale or kelp.

A Compounding Pharmacy can also mix the Iodine solution for you and probly will tell you how much to take. You probly will need an appointment; I paid $35 and never had to return -- she fixed me like NO other doctor ever had. I suffered for years with Brain fog (2004-2014) My brain doesn't feel damaged.

I would like to add--Breathing exercises got rid of Restless Leg Syndrome (RLS) for me, it can relax you and get you back to sleep if you wake up at night.

Ralpert, Also, if your ELECTROLYTES are low one of the symptoms is concentration problems so you might be suffering from this also. Usually low-concentration and short-term memory problems go together. If you want to check this website out for more info. Load up on knowledge so you have an idea on what to work on.

https://draxe.com/electrolyte-imbalance/