Thank God for His mercy and grace in giving you more years to be His instrument, to show His love and Truth in this world, to His glory, as you trust the Lord Jesus to spiritually save you by His sinless shed blood, as one who is as helpless to do so as you were physically to save yourself. May we be to others as the doctor’s hands physically were to you.
I am 67 and have not been under medical care since about 1978, but I do have angina and am getting increasingly tired.
But I almost didn't make it to my 64th birthday because of the problems I described after my open heart surgery.
If you have angina and are getting tired, that is a clear sign that you need to get your heart checked out. Don't wait.
I never had angina or a heart attack prior to my heart surgery but my cardiologists said I could have had one at any time. I had four coronary arteries that were 80% occluded or blocked when they bypassed them during the surgery.
Good luck but go see your doctor as soon as possible.