Finasteride isn't taken seriously and most of them don't know what it is, so I'm reluctant to try and talk about it again.
Show your Doctor this and he should take you seriously. Also, participate in the study if your side effects have not resolved after quitting.
viewtopic.php?f=46&t=58504
what tests to ask for?
There's a sticky post at top of HORMONES section about Recommended blood tests on that "other" site you're also a member of -- suggest you read that. Also already gave you direct links to do so in your inquiry on that forum.