you are working a lot of hours so you maybe suffering from exhaustion, extremely tired, this means you are doing far too much
as for the caffeine this will irriate the
heart and make it beat faster, so cut down the tea,
coffee, choc, fags i know its hard, i get by with one chocy bar a day and i feel a lot healthier change it for fruit, you dont need junk just make sure you sleep plenty too.