Does my ferritin level warrant an infusion?

My ferritin is 9 ug/L, my doctor told me this is ‘a little low’ and has put me on iron tablets. I feel like I am dying every day, my other iron levels are normal and my haemoglobin is 139 so I am not anaemic but feel rubbish every day and have no energy. In the UK, unless your haemoglobin is low you cannot have an infusion. Is this a level where I should seek an infusion and pay privately if needed? Thank you!