Do your doctors test for anything besides TSH? FT4 and FT3 would be very beneficial in seeing what's going on-TSH is handy, but not something to go on alone when it comes to thyroid disease.
I lost weight being hypo. It can happen. I have Graves' and needed two radioactive iodine treatments for it, but before I needed the second round, I was having classic Graves' symptoms except for weight loss. I gained a bit becoming hypo, then lost it again in three months and was losing weight despite a normal appetite. My Ft4 was going higher and higher with med increases, TSH was going better in the range, yet my TT3 was getting lower and lower. Turns out my FT3 is very, very low, and when they added Cytomel to my Levothyroxin mix, I gained some weight back. You could have a conversion problem with taking T4 meds alone and need some T3. You might also need a better look at your thyroid, especially with the Hashi's diagnosis. Have you had ultrasounds?
Do not feel discouraged. Many doctors do not understand the mental effects thyroid disease can have on a person. I was brushed off for nearly a year before someone gave me anti-thyroid meds and was finally diagnosed with Graves', despite weird labs all that time.
You should not stop taking thyroid medication without your doctor's okay.
Just because you haven't gained weight, doesn't mean you're going to keep losing, unless you are over medicated, in which case, you'd need to decrease your dosage.
TSH is very volatile and is affected by many other things. It can vary up to 75% over the course, of a day, so the fact that it dropped on its own doesn't mean that your thyroid is working to capacity, though it may still be producing some hormones. Hashimoto's is progressive in that the thyroid makes less and less hormones as the antibodies destroy healthy tissue. So while your thyroid may be producing "some" hormones now, eventually, it won't.
The loss of your eyebrows wasn't from the medication; it was from being hypo. It's very common for symptoms to worsen or for new ones to appear when one starts taking thyroid hormones, because it takes the body a while to adjust to having adequate hormones again.
If you don't feel any better on the dose you're on, you may need an adjustment in the dosage or even a different med.
When is your next blood work due? There's really no point in doing it too soon, because it takes the med time to build in your system.
Most of us have been accused of being hypochondriac at one point or another. That doesn't keep us from taking our meds.
We need to see lab results in order to give you an idea of what adjustment might need to be made in your med, in order for you to feel well. If you have your previous labs, you can post those and it will give us something to go on. Be sure to post reference ranges, with labs, since ranges vary lab to lab and have to come from your own report.
How long did you take the 150 mcg levothyroxine? Was that your starting dose or did you start lower and work up. That information would also be helpful.