To be frank, I doubt you have any heart disease. It would be extremely rare in someone your age, and you sound like you look after yourself! The only thing that might be important is if your Mum or Dad had serious heart disease and passed it on. That's number 1 - better check that out.
The numbing of the hands and legs is not a true symptom of heart disease. People with some numbing can be very healthy - it can be due to a variety of causes, but LOW blood pressure - a sign of a good heart - can be a cause. On the other hand HIGH blood pressure is a common sign of heart disease, and, from what you say, I doubt you have that. I would be looking elsewhere, perhaps in the nervous system for a cause that better matches the extensive
numbing you talk about. Angina is usually a dullish pain, but is often associated with chest pressure, and is usually exercise-related. Angina is normally found in someone much older, and takes years to develop.
Blood clots don't occur on the way you describe, and if they did you would not be around to talk about it.
The constipation must be unusual in someone so young, and that needs a proper follow up. Don't accept that as a condition you have to live with. It may not be IBS. There are all sorts of options with diet, and medication, if necessary, to tackle that. Some others here may be able to give you more specific advice on the IBS condition.
To sum up, you need to see a doctor and be properly diagnosed
, self-diagnosis is NOT a reliable option.
I don't know much about the US health service, but can't you go as a public patient - you can here in Australia. It's just that you then have to wait in a queue.
You're young, and I assume smart - can you get yourself into ER - I think once you are in they would have to properly diagnose you? Some others might have better ideas. But keep pushing and questioning - that's good progress - well done.