Stuck in a 4lb Range!

Hi,

I've been going to the gym 3x a week for the past 3 months (usually about an hour at a time). I have not moved out of this 4 pound range since I started. One day I'm down 2 pounds, the next up 3. The next, down 4. I never move out of this zone. My husband and I are doing this together - he's losing, I'm not. I have toned up, I can tell I've lost inches, (even my coworks have noticed!) but the scale isn't moving.

What am I doing wrong? I've cut everything, I measure my foods, I count my calories, I'm gong to the gym...what the heck? I'm not asking for a miracle here, I just want to lose one freaking pound to show that something is happening!

Just FYI-
- I'd been using another app to track my calories but nothing was happening. Just switched over to MyFitnessPal on the advice of my sister (who is also a personal trainer.) She lives in another state so I can't have her come help me in the gym!

- I have always, ALWAYS, had problems losing weight. Even crash diets don't work for me. I was diagnosed with hypothyroidism about 5 months ago and am taking medication

- I spoke to my Dr. about this and she said it's because I'm starting from basically zero. I need to build muscle before I can lose anything. Shouldn't 3 months do SOMETHING?