As you say, quite rightly, diabetes is not my forte.
However......you certainly have, unstable diabetes and this is not uncommon in some women (don't know why) and it is also associated with other hormonal problems and you say that you have thyroid problems.
You problems seem to be hypos in the late evening.
My advice for what it is worth:
1) maintain you prescribed Insulin dosage and treat the evening hypos.
2) After your evening meal have a piece of cheese at about 9.30 pm.
3) Check your TSH levels to see if you need to increase your thyroid intake......if you are being treated for an under active thyroid.
The bottom line is that you may have to "ride" this period of brittle diabetes out for a period of time, just treating the hypos as they come.
it happens, it is a miserable disease to have.