What causes abnormal heart beat, chest pain and borderline serum iron levels?

Hi, I am 23yo F with no medical conditions or significant medical history. Drugs - combined oral contraceptive. My problem is that the past 2-3days I am hyper-aware of my heart beat in my body - shoulder, left arm, leg, stomach - I can feel it all the time and the pulses in my neck feel unusually strong, I barely have to touch them to feel them, strongly. Heart rate is higher than normal, although still within normal range (normally = 70-80bpmm now at around 80-90pbm). I am not usually aware of my heart beat. I am in exams so I thought stress might be the culprit but it does not go away when I rest. I often get chest pains at rest and occasionally can feel my heart sort of "gallop" (I saw a doctor about that and was told it was nothing, but might be useful to know). I weigh 150lbs, am 5'7. I have not been active for school reasons, over the past 2 or so months, I usually am. I'd say I could definitely stand to eat more fruit and veg, but I don't smoke, and drink about 5 units per week on average. I am currently on my 7 day contraceptive break and am on my period. Have been told several times in the past that my serum iron is borderline low (have been restricted from donating blood as a result). My BP is usually a little high at the doctor's. Okay, I don't think there's anything else I can add to that, hopefully you can give me an indication as to whether or not this is something I should be worried about. Many thanks :)