Fakestuff

I'm pretty sure I have a thyroid problem. I am a 17 year old male.

I have these symptoms:

I am gaining weight inappropriately - BIG TIME
I'm unable to lose weight with diet/exercise - BIG TIME
I am constipated, sometimes severely
I feel fatigued, exhausted - BIG TIME
Feeling run down, sluggish, lethargic
Dark circles around eyes
My hair is coarse and dry, breaking, brittle, falling out - BIG TIME
I have a hoarse or gravely voice
I have puffiness and swelling around the eyes and face
I have pains, aches in joints, hands and feet
I feel depressed - BIG TIME
I feel restless - BIG TIME
My moods change easily - BIG TIME
I have feelings of worthlessness - BIG TIME
I have difficulty concentrating
I have more feelings of sadness
I seem to be losing interest in normal daily activities
I'm more forgetful lately
I can't seem to remember things
I have/may have sleep apnea
I feel shortness of breath and tightness in the chest
I feel the need to yawn to get oxygen
My eyes feel gritty and dry
My eyes feel sensitive to light
My eyes get jumpy/tics in eyes, which makes me dizzy/vertigo and have headaches
I have strange feelings in neck or throat
I feel some lightheadedness

My question is, if it does come back that I have a thyroid problem, and the doctor gives me the medication:

Would the medication make me better? Like make my hair grow back and get thicker?

Would I need to take the medication all my life?

Are there any side effects of the medication which could make me much worse

My hair is falling out at a very fast rate along with the other symptoms, I get my blood results back Tuesday :/