The last bloodwork on July 8th from my Internest (that I took to the new endo) was when I was on the 90 mg of Armour was TSH 0.08, T4 0.9, T3 was 414, DHEA 82.
Your doctor doesn't seem to have a clue about thyroid meds and proper treatment. You have gone down from 90 mg of Armour ( 57 mcg of T4 and 13.5 mcg of T3, which is equal to about 110 mcg of T4) down to only 88 mcg of T4. Not only that but T3 is much faster acting, so when you change to T4 only, you need to transition, in order to avoid the letdown while the T4 builds up over 4-6 weeks to take the place of the T3. Also, if you are not converting the T4 to T3 adequately, your Free T3 level may be further adversely affected.
All in all, it is no wonder you are feeling lethargic. Does your doctor know that thyroid meds do not cause any bone loss? The only effect from thyroid meds is to increase metabolism and thus speed up bone loss or regrowth, depending on whatever condition you are already in. The way to treat bone loss is to fix the underlying condition, not withhold necessary thyroid meds.
It would be very helpful if you would post your thyroid test results and reference ranges shown on the lab report, so that members can further assess your testing and treatment.
I think you can benefit a lot from reading this link. It is a letter written by a good thyroid doctor for patients that he is consulting with from a distance. The letter is sent to the PCP of the patient to help guide treatment. You'll notice quite a difference from clinical treatment described in the letter and your treatment.
http://hormonerestoration.com/files/ThyroidPMD.pdf
I'm in serious doubt also the lab T3 was done as a free and most likely is a total value drawn whiich is useless. I'm also suprised you have no T4 reading and was "tossed" on a T4 - ONLY medication without that lab drawn at all.
Go back to the doctor and demand better tests before thing get worse. You will need a FT3 - FT4 and a TSH drawn all at the same time to really indicate where and what meds you need to be on. It will be sad that you may have only needed a tweek on the Armour and now that you are on a totally different form of treatment you may be backwards more.