My doc said I’m healthy and gave me the ok to exercise. But yesterday I went for a bike ride and I guess I pushed myself too hard to the point where I felt dizzy and nauseous. I haven’t exercised in months and also it may have been because I only had a iced latte and just a couple of hash brown in the morning. I feel like exercising could help me manage my anxiety but I’m scared that I may have a heart attack or something while I’m going out for a run. 

Any tips would be helpful.