18 months post op 95% removal: returning symptoms

Hi! I had 95% of my thyroid removed 18 months ago, and now many of my symptoms pre-surgery are returning. Excessive coughing, difficulty swallowing, sore throat, "swollen" feeling in neck, hair loss, excessive fatigue, weight gain. I am taking 175mcg Synthroid daily, but that doesn't appear to be helping.
When the surgery was done, the doctor informed me that the thyroid had "turned into a rock" he had to chip out. He said it was choking around my windpipe...surgery took much longer than originally expected. He told me he got most of it, he had left about 5%. Is it possible for your thyroid to grow back??? HELP!!!!!!!

Have you had a recent blood test?
I went from being hyperthyroid to hypothyroid (radioactive iodine treatment) and if my dosage is off I feel as though my symptoms of hyperthyroid and hypothyroid are returning depending on if dosage is high or low.
I once took generic thyroid medication and after 1-2 weeks could tell the medicine was not doing the same job as name brand. That's how sensitive I am.
Maybe Synthroid itself is not working for you and you should try another type of thyroid drug. My choice is Armour Thyroid. I did not do very well on Synthroid.
Doctors, for some unknown reason, seem to hesitate when people ask to try Armour but if you want to give it a try BE PERSITANT. It's your body.
Another thing...when I first had thyroid treatment the specialist told me I needed to take anti-depressants too. I thought she was full of it and refused to take them. Then about 2 yrs later I went to my family doctor complaining that I just "didn't feel right" stating I thought my thyroid was amok. He gave me anti-depressants and I started to feel better. You may want to ask your doctor about that too.
Hope this helps...I've had thyroid issues for 18 yrs and I think I've been through it all...and I know it can make you feel really bad.
Good Luck.