Burning and Numbness in one foot

:sick: I'm struggling with exercise at the moment due to a burning/numbness/tingling in one foot which starts around the toes (two next to little toe) and then spreads across others and into the rest of foot (including heel). This foot eventually goes partially numb/burns and prevents me from carrying on. It only happens in one foot.

I've had the numb toes thing from using the Elliptical trainer before, but this new foot pain occurs with any type of exercise now (happening for around 2 weeks in total) and also happens to a lesser extent when just walking.

I've obviously tried different shoes/trainers and tried resting my foot up between days. And I've also tried barefoot too.

Been to the Doctors today, but he had no ideas and said I'd have to wait for various blood tests which he can't do for a month (good old NHS).

I'm desperate to carry on with exercising since I'm 1.5 stone into my intended 5 stone weight loss. Does anyone have any ideas on what this could be and how I can prevent it?