elevated heart rate

Is it normal for there to be elevated HR? I last took this two years ago and we got off it because of QT syndrome. I have had to take it intermittently like twice for a few days to reset sleep and did 50mg. We wanted to try again because it was beneficial last time and figure the QT is dose dependent. I am on 25mg (two years ago 200mg). I have been taking last two days and have had elevated heart rate that keeps waking me up. My normal is 70-80 and even less when sleeping but now, it's at 95-105 upon waking and it stayed this high nearly all day yesterday until about the 20hr mark after taking it last. I slept the first night after waking up 2.5hrs later from HR and was able to sleep 6 hours restfully but I just woke up just now after 4-4.5 hours and I am just so uncomfortable due to HR being 100.