Happened to me the first few times. I noticed it so much, my chest was always so warm and my heart was racing. It still happens when I get too high but it doesn't bother me that much since I have a cure. Most of the time you have to have total control and stop all thoughts, sit on the floor and just try not to breath heavily because remember constantly doing this sober can make you lightheaded and already panicking doesn't help, so just try your best to breath normally and just chill out. In a few mins it'll stop and you'll be fine, you go up the roller coaster and now you just have to wait a min to go down the roller coaster and it'll be all good the rest of your high .