I disagree slightly with the thought of targeting TSH as part of hypo treatment. Yes the TSH of 143 is very high and must be reduced. But the real objective is to test and adjust FT3 and FT4 levels as required to alleviate hypo symptoms. Whatever medication and dosage is required to do that will also result in some corresponding level of TSH. Since TSH is a dependent variable, you cannot adjust both FT3/FT4 levels and TSH independently.
It doesn't look like you are going to the doctors enough to get stable on the medication.. I would guess that your levels fluctuated due to having a baby and a condition called post-partum thyroiditis "this can make you go hyperthyroid for awhile after you have a baby and a have a reduction in meds but then you go back to being hypothyroid and now you are primarily hypothyroid and need more Thyroxin.
You should make an appointment and have your TSH, Free T4 and Free T3 and work with your doctor to increase your meds and go back every 6 - 8 weeks to be re-tested and adjusted until you feel better.. You need a higher dose of medication with that TSH level.. your TSH should be around 1 or 2 or somewhere close, but not 143..
In order for members to provide you the best advice, we really need to be sure about a couple of things. First, were those tests results for Total T3 and Total T4, or Free T3 and Free T4? Second, since lab results can vary from lab to lab, and they sometimes use slightly different ranges, we need to know the reference ranges used by the lab that ran the tests. Also, did your doctor reduce your medication because of the low TSH result?