Glad you know the CBT appt & have met the psychologist before . FDH's *'s website will point you to good info & remind you how many people overcome their anxiiety and keep on top of it .
Completely agree re :urging you to check , at an appropriate time , whether you're having thyroid problems or hormonal changes , as over the years I've often blamed myself for not using calming techniques effectively without realising there was a physical reason why the stress response was easily triggered !
If the studies on childhood stresss are accurate , being a carer for your Dad , & worrying about him , on top of your parent's split , may have sensitised you to stress - severe / sustained stress in childhood affects you so incredibly strongly & fundamentally , IME .
So sorry you lost your parents early on , & your Mum when you so needed your mother .FDH is surely right that it's tied in with being the age your DM was when you lost her - sorry FDH for your Mother's premature passing , & for the recent loss of your Father .. I've had disruptive bouts of minor health problems plus anxiety then realised they coincide with something associated with bereavement , & they faded away on their own. ( not suggesting your current symptoms are minor , but that grieving can be very physical ).
Brilliant that you have some breathing space . I think you did really well not to beg the GP to examine you ! Do think she spoilt it a bit by saying you'll just have to believe what the doctors say : we can't trust in a vacumn , & need to take into account our experiences , our situation , how balanced our judgement might be at the time , health info & statistics ( & then we have to work out how far we should believe them , but may have to give up at this point ) ....
If symptoms carry on / worsen over a moderate period of time , & balanced source (s) of info point you to go back to the GP , eventually further checks will be made - so you don't have to trust for a long period of time ( erm. ... I'm sure GP took it for granted that you know this , but I don't think she should have , as nothing is "obvious" when you're in a state of high anxiety - I couldn't trust my judgement on the subject I was worried about , especially as we also feel shame for having health anxiety ).
Hope the increase in dosage helps you get over this v rough patch , but take care of yourself as you might get initial sideffects which affect you more than they would usually .
Glad you have a referral to an Endocrinologist , FDR, as some women suffer years of problems which might have been treated.
Hope some rest , the website & resources help you through till the CBT kaylasmum & sorry for inability to write concisely.