I was told I have Graves but I gained weight PRIOR to MEDS..any thoughts?

I went to the endo dr because I tested pos for ANA and my auto immune numbers for thyro were over 900 that were suppose to be under 20 and then the endo tested one of the numbers that indicate graves @ 200 an extremely high number...and at risk of heart attack if I don't medicate..So why did I gain if I had such high anxiety and everything was going so fast? I should be skinny or thin like I was, does anyone know? My blood has been sent to a auto immune specialist in LA but just want to see if anyone has thoughts for now? Im sort of nervous..I've been very ill. thanks