Yep that is par for the course. The dose doesn't matter per say as everyone has different sensitivities. There does seem to be a correlation between dosing and the more obese you are. For example I struggled mightily on Reta especially once I got to 2mg. I'm already lean and was using it as a test to get rid of some lipomas, which did not work. Reta can also be hard on IGF-1 one levels, hence the muscle loss. If you can't get your proper protein or calorie intake, you flat out need to lower the dose. That's your main problem. Higher dose does NOT equal better results. Find the sweet spot and stay there.
The food-noise switch-off is the same circuitry that also turns down a bunch of other “wanting.” Work and gym usually stay intact because they’re scheduled/habitual; the optional stuff (hobbies, music, random projects, even some social stuff) just goes quiet. People describe it exactly like you did: not sad, just uninterested. I hate the exact same symptoms. Even sex at times wasn't that interesting.
On whether it wears off after the first month: No. Yes the body can adapt, but I'll point you back to the first paragraph about under eating. Fix that and get some good carbs in you and I think you'll feel much better. Plus lower that dose.