My resting heart rate used to be around 60. And 60-70 while sitting. I'm not active at all, never exercising or anything. On Wednesday I was exercising for the first time in a very long time. That night I suddenly felt that my pulse was very high, around 100 while doing nothing. I got an anxiety attack and my pulse went up to 145!! Usually when I have anxiety attacks my pulse is around 60-80. I'm anxious all day. I'm also afraid of having a blood clot, so I'm thinking that since I was exercising it might have been going to my heart giving me this high heart rate. So, for almost a week now my pulse has been constantly around 80-120. It won't go down. Not even when I'm lying down. I'm used to my pulse being so low and was always worrying about that, now I'm worrying about this constant high pulse. I'm only 16 years old. I went to my doctor before for my low pulse, and got an ECG which was normal. But why am I suddenly having this high heart rate all the time? My doctors appointment isn't before the 22nd October. My parents couldn't care less. I'm really worried. And it doesn't matter if I'm taking my pulse or not because I can always feel it everywhere in my body. Oh and btw my doctor just told me that I have iron deficiency. But that can't be the reason for my heart rate since this just started in wednesday...and I'm also feeling worse everyday, dizzy, tired and nauseous a lot. I'm really confused please help. Sorry for my bad English, it's not my first language.