I ran 3 miles yesterday. 3 months ago, I could barely walk without breaking into a sweat. God gave us pasta, corn syrup, and white bread so that is what we must eat, according to these idiot debunkers.
I am not an Atkins absolutist though. The key for me was to stop eating unnatural things. Once you start eating only as God has provided, you find out you are going to do ok. If you want to eat brown rice, go for it.
Low/smart carb diets should be called the "Creator Diet".
I hope that you at least have had an ECG or, better, a thallium scan. If you were as out o shape as you describe, you may have a nice case of atherosclerosis solidly underway.
A stenosed corornary or carotid artery + a blood clot or fragment of an arterial plaque == goodbye dogbyte12 + a sad thread on the FR.
I'm not slamming you, but rather am begging you to consult a cardiologist for baseline studies (including lipid, electrolyte, and coagulation profiles). It wouldn't hurt to get yourself checked out for Type 2 diabetes as well. Any family history of diabetes, stroke, heart disease, etc.?
BTW, although not an MD, I am a Ph.D. (1978) biomedical scientist who likely has the time and job mandate that allows me to read more medical journals, writes more journal articles, and attend more conferences than your family doc. But this is not about me by a long shot. It's about you.
All the best, and stay well, bro......