Ashley.
I am so sorry you are suffering so much. Hang in there and work at it you will find the answers you need.
I read the replies posted for you, and most may have some benefit for you. The symptoms you listed are very similar to those of hypothyroid, the question is why low thyroid function. During pregnancy your baby can actually helps supplement thyroid for both of your benefits. There are a lot of questions that need answers before you choose a path.
Have you had your TSH, T-4, free T-3 levels checked recently (when)?
How was it determined you were hypothyroid when you were younger, what did they do for it, how much did it help?
Are you eating any foods that harm thyroid function, ie cabbage, broccoli, spinach, turnips .......?
For your information thyroid hormone has a vast number of functions within our bodies from helping convert beta-carrotine into active vitamin A, to helping give you a healthy smarter baby, just to name a couple.
There is some evidence that not all thyroid hormone is created the same, without boring you on the chemical explanation, reverse T-3 may compete for binding sites with the regular (good) T-3. If this condition exists medical tests would not distinguish between good and reverse forms of T-3 thus showing normal levels of the hormone but actually show clinical signs of hypothyroid. Read Denis Wilson's book (Wilson's Syndrome).
Thyroid hormone is made of Iodine a mineral and Tyrosine an amino acid (a building block of protein). Conceivably low dietary levels of either could give you similar symptoms. DO NOT SUPPLEMENT WITH EITHER THOUGH, work with a DOCTOR on this. Both iodine and L-tyrosine can be dangerous under certain circumstances.
You should also be aware that your symptoms may be indicative of Chronic Fatigue Syndrome. Check out spam link for some good info on that. One of the more successful treatments for CFS includes low physiological doses of T-3.
My suggestion for you to try for three weeks or so is simple, safe, and surprisingly effective. Oh ya it is also basically free. Stay away from all caffeine (it dehydrates you), eliminate all soda pop. Start your day with a pinch of sea salt on your tounge and wash it down with a 16 oz bottle of water. Drink at least four more bottles of water through out the day, and prior to bed wash a pinch of salt down with about 10 oz of water. In addition if you avoid sugar and high gylcemic index foods and replace them with proteins and low glycemic index carbs you will have a great start on getting better.
Good luck!
Smile God loves you!
Let me know how you are doing and what helps.