It will be hard for you, because your thyroid regulates A LOT of stuff. The hardest part will be finding a doc who is willing to adjust your meds according to how you feel, not what your tsh, t3, and t4 numbers are.
Since you are having yours removed, I would suggest you do some reading about Armour Thyroid. It is natural, as opposed to synthetic drugs like Synthroid or levothyroxine.
The biggest difference between the two is that they synthetics only have replacement t4 in them. Armour is made from pig thyroid (I know, gross), so it has the exact hormones that our thyroid produces. T3 is VERY important to energy levels, so if your doc puts you on a synthetic and you are not feeling like your old energy is coming back, give Armour a try.
A lot of docs do not like prescribing Armour, and prefer to go synthetic, so your doc might even say no to it. I have my reasons why I think that is, but it's not important right now.
Yes you can feel normal, no you don't have to weigh 300 lbs., (I am 5'10 and weigh 128), and I understand that you must be scared.
Here is a great site with other thyroid patients, many of whom who have had the same procedure. You can get a lot of answers on this site, plus talk to others about what to expect in your surgery, during recovery, and after.
Feel free to FReepmail me whenever you want. I have been going through this hormone craziness for two years, and I still have more tests to go, with more meds to take. Arggh.
thank you - that is helpful. I'm on synthroid now for Hashemoto's and the doc said I would be on something different after surgery but I don't remember what - the whole appointment is kind of a blur now. But I'll be doing lots of reading in the mean time. Thanks for the info and the link!