Welcome to HealingWell. I do not have a cardiac problem but last August 10, 2012 I was dx with Colon Cancer, Stage IIIC which is serious and I felt as you did. I remember lying on the cart in the prep room all alone with tears rolling down my face and my family was in the waiting room and I prayed I would see them again...............the thought that kept going through my mind was I am just 66 and I don't want to die.
I already had a 30 year history of anxiety and depression so I questioned why I would now be given cancer.
So here we both are, still with our families and like you I have many worries but am trying to deal with them without making the thoughts bigger than they need to be. I also have learned to be more assertive and advocate for myself instead of worrying about a question that never got addressed by the Dr.
In other words, YES, waiting until October is to long with the symptoms you are having and the Exercise Tolerance Test results. Get that referral and see the Cardiologist.
I will be praying for you, Sharon and hope everything turns out well. Do keep us posted and come here and share your feelings anytime as we are always here for you.