You may have low adrenal function with hypothyroidism as secondary.
In low adrenal function, the adrenals down regulate thyroid function for adrenal recovery.
Low adrenal and low thyroid function are the main reasons for consistently lower than normal temperatures (except when having a infection).
One main feature of low adrenal function is a high level of cortisol, when there's unresolved biological and external stress, which over time cannot be sustained, leading to low levels of cortisol.
Cortisol regulates the immune cells in our gut so when cortisol is depleted those cells become dysregulated, making us more susceptible to pathogens like bacteria, yeast, and parasites.
When you're having a low grade infection, this co-relates to a low grade fever,which in your case is lower than people with normal thyroid function, however, your higher temperatures, co-relate with more acute type of high grade infectious conditions.
The fever, having a therapeutic purpose, in the body's response to infection, may be much more effective in the higher temperatures,
but one thing to note is when taking your temperature, use a glass thermometer, which is more accurate than digital.
If you need more details in regards to low adrenal or low thyroid function,
let me know.
Conventional medicine is doing a mediocre job in addressing hypothyroidism, using flawed testing and ignores any adrenal issues until
they reach a crisis level!
Hope this helps, however, my comments are not intended to replace medical advice.
Best wishes.
Niko