Hello. Please don't fret/ panic and feel isolated by all this. I have found well meant advice on communities a bit daunting when they require you to do things that you just can't envisage doing.
The advice is often very good and sharp but the reality is that you may already be gluten free, living an optimal lifestyle etc and still be feeling rubbish - as I often am. Also, getting printed results off your GP can be much harder in some practices than in others. My current practice, for example, makes it impossible for patients to get their blood results printed off apart from asking GP to write them down. They tell you if anything is wrong then the GP will phone - they won't print off because "if everyone asked then we would be printing constantly". I don't want to risk angering the GP or reception because I have to choose my battles carefully these days. But if I want them enough I will tell small white lies about needing them to email or show them to a private consultant. They don't like it but have reluctantly obliged so far. The NHS can withhold this information by law or make you pay for print outs or buy a copy of your records I believe. Different practices have completely different policies.
I would advise that, as well as considering that doctors may be wrong, you also consider alternative reasons for your unwellness as I am doing just now. Not everything comes down to B12 or the thyroid - although with high antibodies it might in your case. If you have been diagnosed with Pernicous Anaemia you will be taking B12 already , and your results will obviously reflect this.
Other less common autoimmune diseases, such as Sjogrens, Vasculitis, Lupus and RA are all systemic too and can make you feel rubbish - as can Coeliacs Disease and under treated Pernicous Anaemia (PA). I don't know this for sure but I think they can probably cause high thyroid antibodies too. And there can be plenty of crossover with other, rarer autoimmune diseases.
The best way to try to make progress in my view, is to go back to the nicest GP in your practice and explain how you are feeling and discuss. Also ask, as nicely as possible, for your blood test results so you can learn to understand it all better for yourself. If this doesn't work then offer to pay for print outs - if necessary reminding them firmly that it's your body, your blood and your health that is at stake.
If they continue to offer you antidepressants then I suggest that you politely decline and point out that it seems odd to you that they are treating your thyroid by blood results alone rather than symptoms - but are simultaneously offering you powerful antidepressants, that can cause a whole host of side effects and problems (and hellish to get off!) despite having no hard evidence that these are needed or will help. Again I try to find a balance between being polite and friendly but firm/ assertive.
This advice is born of long experience - but you need to follow your own instincts about what approach works best for you. I hope it at least helps a bit. Meanwhile go gently with yourself if you are feeling lousy - and try to be methodical as possible in working out what is causing what - keeping a symptoms journal is a good idea if you can find the time. Twitchy