18 year old female, 130lbs, blood pressure usualy between 90/45-80/40. Resting heart rate around 90. Low ferritine level (9), borderline full blood count. EXTREME tierness (feeling sleepy at 6.30, going to sleep at 8, waking up at 6.30 and still feeling tierd). Diagnosed with asthma (getting immunisation for that). I am taking iron supplement twice daily for the last 11 months. Condition worsining. What can be wrong? (Iron test is borderline). I seem quite healthy... Relativily. Often sick. Have had both 'types' of glandular fever (mono). I have taken iron supplements since I was about 6. Was fine for a long time, then deteriated after a bad illness (do not know what it was). Really want to just get my energy back. I have vitamen C supplements as well...

Any ideas?

Thank you