Your heart is not designed to be pushed by chemical substances, whether they are amphetamines (legal, I realize), cocaine (illicit use or abuse of medical grade cocaine used as a local anesthetic), caffeine, energy drinks, or otherwise.
The use of your medications, as prescribed, has relatively predictable side effects, the use of more than directed is never to be done. In addition, combining Adderall and/or Vyvanse with caffeine and/or energy drinks should not be done. (I'm not talking about a cup of regular coffee every day, I'm talking about hi-test coffee [high caffeine] or multiple cups of regular coffee). In addition, other substances can have dire effects on heart rhythm, such as high amounts of B-Vitamins, and various "natural" herbs or supplements. Natural does not mean safe, cyanide is natural, we all know it's not safe.
You need to drop back and punt. If you have more problems, appeal to your father about visiting the E.R. again. If things seem to be settling, suggest a visit to your family physician just to touch bases, or even a phone conference with him/her (they often have someone on-call) tell him/her all the medications, energy drinks, and other substances that you use, such as over-the-counter medications. You need to take your life seriously, too much stimulation is not good for heart rhythm just as too many depressants (narcotics, alcohol, tranquilizers) are bad for respiration.
Hi I'm not a doctor, but if it were me and I had additional concerns, I would not fret. I would just call the doctor, or go back for additional medical help. This would help me sleep better, especially if I found out that my new symptoms were not a problem and got to go back home again. No one, no one, would hold such decision against you, if you only were attempting to err on the side of safety.
How you handle your dad can be a separate matter. But, keep the fools choice in mind here. This isn't about who's opinion carries more weight (your fathers or yours), but about ensuring your personal safety. I am sure you will fairly weigh your father's opinion and everything, especially if he is a medical doctor, and then make the final decision on your own. You both share the same end goal to ensure your health and safety, so the fools choice is not the choice you will need to make, even if you anticipate a difference of opinion.