Could an iodine deficiency cause sudden weight loss?
I had a similar period of drastic, startling weight loss when I was at uni, and it sounds as though your circumstances are very much the same. It turned out to be simply not eating enough for me, I was very busy and would just forget to eat and not realise until I felt faint. EAT MOAR! I eventually learned to set an alarm to remind me to eat, and carried food with me everywhere and made sure I wasn’t skimping on fat and salt (I also have low blood pressure, and through this period had more ‘spells’ than at any other time in my life). I also started taking a multi-vitamin (although tests didn’t identify any notable deficiencies) and it seemed to help (possibly placebo). Also, for me the amenorrhoea was directly caused by the weight loss – get your body fat to over 8% and your period will return (and your arse will hurt less when you sit and the soles of your feet won’t hurt anymore from walking witthut any padding). Good luck! I hope you’re feeling better soon.