Getting worried after subtotal thyroidectomy!!

Hi there

31 year old male.Had a partial thytoidectomy on Aug the 6, 2010 for a toxic nodule. Before the surgery in a 3 month period I have lost 15kg (33 pounds) probably due to the hyperthyroidism symtoms (symptoms).Was 105kg,at surgery 90kgs. After the surgery for about a month my weight stayed the same as the day of the surgery.

Now,the last couple of weeks I have noticed Im starting to lose weight again.Im really getting worried now as I am about 6 foot 3 and starting to look ''underweight''

I am currently on Euthyrox 50 (Levothyroxine) which I started using 10 days after surgery.Can the ''leftover'' thyroid produce enough hormone that the meds are causing some hyper symptoms again or is the dosage of meds too little?

Has anyone experienced anything similar to this?

I am really worried and feel that my life will never be the same.Is it normal to have so much unintentional weight loss before my surgery with hyperthyroidism and will I ever return to normal again?

I will be going for my first blood tests next week.

Many thanks