your medically qualified relatives don't accompany you to work though - and clearly something in the work setting was comples enough for OH to get involved/ ask for referral to specialist.
i don't believe the specialist had 'simply been a bit busy', just read a letter and prescribed you medication without assessing you. and i don't believe subsequently that a very senior consultant would have prescribed you further medication to counteract side effects if he/she believed that the original medication was prescribed in error.
whether or not you believe you have a major/ minor medical condition, you need to make an appointment with whoever the specialist is for this dx, to discuss your treatment plan and the dx, if you wish to challenge it.
the fact that you seem to have been through some of this before wrt your relatives (implying that they 'always do' look after you medically when you need it) implies that you have some ongoing issues which may have been complicated by different specialists being brought on board/ referred to by OH.
do you have access to any community psychiatric help? i'm assuming that the issues are of an ongoing mh nature by your reticence - my apols if this is not the case.
if you are reluctant to trust the specialists you have been referred to, i would make an appointment with your gp and ask them to intervene on your behalf. they will take your opinion seriously and take into account any existing or historical issues.
fwiw, if your OH dept were merely in it for the money, finding a reason to sack you, rather than refer you for help, would have been far more beneficial for them. is it possible you have misjudged the situation?