I am a 16 year old male who is having really bad headaches, and is having a hard time seeing... I also checked my heart rate, and it is going down. I have been resting for about 3 hours now, and checked my heart rate at 9:30 and it was 75bpm, then checked it at 10:30 and it lowered to 55bpm, now I just checked it a minute ago and it is 35 bpm...