It is generally used for type II diabetes, but maybe you have some insulin resistance or pre-diabetes, which could also make it difficult, if not impossible, to
lose weight.
That may be why you were prescribed
that. It is also used to treat PCOS - do you know if you have that? Is that why your cycle is irregular?
Did you have other thyroid tests done (Free T-4, Free T-3, etc)? I'm sure there will be others who can tell you more about the other meds.