What Causes Heart Palpitations Along With Vertigo And Dizziness?

I m going straight to the point here. As of right now, July 7th I think and feel as if I m having heart palpitations (skipping beats most of the time and two cases of extra beats). I started noticing this skipping beat after an event/episode that I never wanted to occur again: SVT. During a sport of Frisbee in April 2016, I had to call and ambulance because I was running around strenuously for 2 hours without stopping or resting. The paramedics recorded my heartbeat to be around 230-240 at that time. I was then put onto a stretcher and I told the paramedics that this happened before and I had to bend over or do something to squeeze the blood back into my head (the symptoms I had during this event was lightheartedness and blacking out). The paramedics told me to blow through the sharp end of a syringe tube really hard which made it go away and I had my high pounding heartbeat back (I now learned this is called a vagal manoeuvre). This SVT event was the 3rd time that happened in my life and I m currently 18. I had an event during the same event when I was in the 7th grade, the second one was during the same frisbee event a month before April and the one I just explained above. At my visit to the hospital, I was looking at my heartbeat on the monitor and I saw that I was beating at 100 bpm for a while (30 minutes or so). That was the first time I went to the hospital so I was scared and nervous. I looked at the monitor for a minute and I saw a space between the blips of the heartbeat which I did felt in my chest as a sense of chills going down the back of my spine and a sense of lightness. This worried me even more. I was sent to a cardiologist named Camden Hebson in the Georgia where I was given an event monitor to wear for a month and a EKG. Dr. Hebson told me I had SVT with aberrancy. At the end of the month, the event monitor was was looked over by him and he said that everything was normal. I m still curious because I tagged the event where I had heartbeats skipped and I thought he would say something about that. As time passed I went to school like normal sitting for long periods of time in class when suddenly I had the same skipped beat followed by a feeling of chills going down my back, the feeling of burping or at least a bubble-like bump sensation at the bottom of my throat and a sense of lightness. This was annoying because I noticed when I sit down for a few hours during some mornings and nights, a few hours at school, or a few hours anywhere I get a skipped beat which I notice. I then started to feel my pulse in my neck every time I felt uncomfortable. This made me more anxious and I just constantly tried to measure my pulse whenever I think it may happen again. I had a skipped beat once bending down to grab my shoes (followed by the same symptoms), when I was at my high school graduation sitting down and standing up ready to move, once while urinating, and once while watching a 3 hour movie like everybody else. During the month of June I went on vacation to Cambodia and I was also uncomfortable because I worried that the skipped beats may happen again. Upon arrival to Cambodia, I was jet lagged and I felt motion sickness due to turbulence on the plane and I just felt as if I was still riding on the plane a day or two after I arrived. I had a heartbeat skip again on the plane when it was night and while watching a movie (the plane ride was more than 14 hours + 5 more). Now that I m back home in Georgia (arrived july 15, right now it s july 19) I still feel a little dizzy which is weird for me now. While I m sitting here writing this every few seconds to minutes I fee a sense of vertigo and slight dizziness (I m not sure if this had to do with the plane ride since). Today I m still jetlagged and I was watching a movie while feeling my pulse during the time. I was so focused on my pulse to detect the missed beat that I ended up feeling skipped beats! I researched a plethora of sites to determine the causes of palpitations and most of the suggestions don t apply to me: I don t drink alcohol, caffeine, do drugs, but I am stressed a lot due to school. I don t think stress is causing my heart palpitations because I m so used to stress that I never notice my heartbeat skip or any symptoms of heartbeat skipping. I m noticing it more after my second SVT event. The SVT ONLY happened when I m running excessively or at least sprinting every few seconds. I stopped Frisbee to prevent any SVT to reoccur again. The doctor prescribed me with nadolol which I used twice because I was so nervous whether or not my heart rate was high. I meaused my ehart rate once at 110 bpm because it was pounding and racing but in hindsight I think I was really anxious and I took the nadolol with side effects being sleepy, tired, fatigue, and dizziness. I don t think nadolol neither helped me or harmed me.