Hi
you need to cut out all caffeine-i also had a high heart rate-like yours (in the 100's)-it took about a month and half but now my heart rate is in the 80's and when i'm resting it's in the 70's. It will be hard but it does work and you slowly get use to feeling good without that drug. You need to change your diet too. I don't know what it is but your too young for these problems and they tend to worse with age.
I suggest going to see a nutritionist but if you can't I am reading the china study (it just came out) and it talks about how food tends to be the problem with our health (cancer, heart attacks and stroke) how to cut out all animal source foods-
take things one day at a time but move forward and you'll be fine