What you are describing doesn't sound like it's being caused by the palpitations. I would see a doctor.
I hesitate to suggest given you stomach upset condition, but if possible an aspirin (or 1/2 of one, or a low dose) a day with a meal will provide you with some protection against clot formation which could be (low probability) formed by a fibrillation in the atrial chamber(s).
Then you must see a doctor and have a general check-up. Best if the doctor can do an electrocardiogram (EKG). My primary care doctor does do an EKG as part of my general physical. So, I know it is possible to get an EKG without going to a cardiologist, and given your other symptoms it is best to first take with a primary care doctor.
Sorry there are no home-remedies I can recommend, sometimes we simply have to see a medical expert. At your young age you should have the strength to get better fast once a problem has be isolated.
Best of luck,