Symptoms of hypothyroid

A while back I went to my doctors and explained feeling tired all the time my b12 and iron come back low was prescribed iron tablets and told to eat more red meat( which I do anyway) Since going I've got more tired brain fog can't function properly face puffed up all time eyes red gritty and I've gained almost 2 stone over a year. Eyebrows have been sparse since around age of 18 I'm 26 now hairs brittle ridged nails. Should I ask for my thyroid to be tested. I'm so fed up of feeling way I do on a daily basis I'm exhausted

Yes but you should also repeat your iron, b12 and ferritin tests. 

I agree.. get your thyroid level checked and also the iron and B12 again.  Those 2 alone can cause your symptoms.  Vitamin D test will be helpful too, as a deficiency can cause all those symptoms too, including the weight gain.  Vitamin d deficiency, is actually very common now a days, but doctors seldom check.