I would go back to the doctor and let them know your symptoms. They should at least get an echo done if you haven't had one. If that is fine then it likely isn't something too concerning. It could be ectopic beats, pacs in the atria or pvcs in the ventricles or it could even been stomach issues. It can be hard to tell cause sometimes stomach issues mimic heart issues and vice versa. When I have acid reflux or indigestion going on it can affect how I feel my heart, make it feel like it is beating fast or hard. It could be my body is working harder on the stomach or it could just be irritation from the stomach is pushing up on the heart since it sits right under it. Either way go back to your regular doctor and tell them the symptoms are persisting and you want to investigate further to make sure it isn't a heart issue. With doctors they a lot of times brush things off and see if the problem goes away and by coming back with the same symptoms that are persisting it gives them a reason to issue tests that can be expensive. It's like stop gap to make sure they aren't ordering excessive testing for things that are only minor or temporary. But it would be good to have a few heart tests done to rule out any heart problems. If they come back normal then it could be simple things like acid reflux, ectopic beats or even anxiety but things need to be ruled out too. So just go back and tell them the symptoms aren't going away. Best of luck. Keep us posted on how you are doing.
Do you know how fast your heart was beating? I can't say for sure what you are feeling but dehydration from a night of drinking alcohol and energy drinks can cause sinus tachycardia into the mid 100s or more. As well problems with the stomach can also cause the heart to beat fast and irregular. I suspect that the drinking you did irritated your stomach causing it to affect the vagus nerve which then triggers the heart to either beat fast or have extra beats that feel like skips and pauses. Chocolate does it for me every time. As does caffeine, carbohydrates and eating heavy or spicy meals. Acid reflux will cause me to have bad palps for days. I would say try to take some OTC antacids and see if it helps. Not just the tablets like Tums for temporary relief but the full pill like Zantac. That one works well for me. Also make sure you are drinking lots of water but do not over drink when eating a meal. Try those things and see if it helps. I hope you feel better soon. Keep us posted on how you are doing.