Synthroid and dizzy spells

I was put on synthroid a year ago, due to a tsh level of 87. I pretty much felt better right away after taking it. First I took 50mcg and then it was upped to 100mcg. Everything went well until I had my latest tsh test. The level was going up again (tsh 5.4) so the doctor decided to put me on 125mcg. After about a week I began feeling like crap. Slugglishness, tiredness, muscle pain, joint pain, and it became progressively worse. I have an appointment coming up thank god. In the mean time I read 3 books on thyroid and it was mentioned that most people don't benefit from just taking T4 (ie. synthroid), despite the fact that the pharmac. and some docs say that body breaks t4 down into t3.
Some people's body cannot successfully break it down enough, some are cellular resistant to thyroid hormones, and those people absolutely need t3 in order to not develop Hypometablolism. The cell need the T3 to function. But unfortunately one can be hypo and still have good TSH levels, because this particular test only tests if there is enough T4 in the body.
Unfortunately, it's so hard to explain that to mainstream doctors.
One doctor I read about said it right: Don't just treat the test results but also the bodily symptoms, for everybody is different anyways. Just like our finger prints are unique, so is our hormonal metabolism.
I'm going to try to talk to my doc about this, but if he doesn't listen I will look for another doc until I found one that will. Good luck to all in this hormone jungle.