Hi Again and Welcome to HealingWell!
It would seem that you are very knowledgable and that you're on the right track here with your health. I understand completely about the concern with your health, especially with loosing your Dad at such a young age. I'm very sorry for that.
Playing basketball is a wonderful sport and I know you're getting a lot of exericise doing that, but I also know that you are probably taking a lot of breaks? and stopping to rest? That's where walking or biking come in and can offer you more of a continuous cardiac workout.
I know this is very hard, but you need to really start focusing on you and your life right now, so you can move forward. What my suggestion to you right now is to go to your Dr. and express to him/or her what your thoughts and concerns are. Do you have insurance? They do have a CT scan that can check for blockages, and this may be an option for you. It's a non invasive procedure. Ask about this and see what they say.
Keep me posted and let me know how you are doing~congratulations on that tremendous weight loss! WooHoo!!