Hello and welcome to MedHelp's forums. We appreciate your question and are glad you have been working with your own doctor. We encourage you to continue doing so. Your heart rate while on the slow side 'may' be normal for you. Particularly healthy and younger people can have a heart rate below 60 and it is 'their' normal with nothing being wrong. Is this what your doctor is suggesting to you?
If your doctor does not believe this to be just the normal situation with your heart rate, there are a number of causes for bradycardia. https://www.mayoclinic.org/diseases-conditions/bradycardia/symptoms-causes/syc-20355474. A full examination and physical would be in order. While it could be heart related, it could also be related to a slow thyroid.
There are lifestyle things that can help which would include eating properly, getting sleep and physical exercise if you're cleared to do this. Also, not smoking is a given in as well as nothing more than moderate alcohol consumption. Reducing stress. Maintaining a healthy weight. The attached article has information on all of these things as well.
Lastly, if you have other symptoms develop like chest pain, fainting, or difficulty breathing for more than a few minutes, please seek emergency care.
Let me know what you think of this information. Best of health to you.