Weight loss with thyroid problems

Ta
So I was recently diagnosed with Hypothyroidism after showing a lot of the symptoms, especially weight gain, and the fact it runs in my family.
I'm 20 years old, small/medium body type and 5ft 6in. A healthy weight for me is between 120-155 and I'm currently 170-180 with a new double chin and stretch marks that I never had before the weight gain. I've been taking 75mcg of Levothyroxine for a bit now and my thyroid levels are back to normal. I'm eating better, lightly active lifestyle and trying to drink my daily water goals again but I'm still gaining.. No weight loss at all and it's super upsetting.. My doctor will not help me with the weight so I figured I'd ask here hoping some of you gals may have or are going through the same thing... Can anyone give me advice and tips ):?
This has gotten to the point where I'm crying every time I look in the mirror or put on clothes... I avoid most mirrors now..