Question about " sudden death" diseases?

I know three people who have died of Pulmonary Embolism/Blood Clot/Cardiac Arrythmia, two healthy middle aged women and one very young adult. I've been reading up on this disease that seems to strike most unexpectedly, healthy people and causing death so suddenly. Right now I'm sick with a nasty cold/cough, chest/rib pains. I've been to the doctor today and had blood work and they turned out fine, just indicated that I have a cold. Yet I'm still very anxious with thoughts that I might get a blood clot. I know it's dramatic but I tend to think of the worse especially when it's happened to people I know. Can someone please help rationalize my fear of the chances of developping a fatal blood clot/Pulmonary Embolism/Cardiac Arrythmia by providing me with some info about its symptons, why it occurs, who it happens to etc. I tried googling it but it just made me more anxious.

do try to see a cardiologist if you are still worried about your condition.
basically, sudden death is explained because the cause of the death sometimes cant really be figured out. We probe that it's due to sudden heart failure, sudden VF (ventricular fibrillation) attack that leads to asystole (heart stop beating).
These are more common leading to sudden death rather than your blood clot issue cuz that may lead to a heart attack or a stroke, much less a sudden death. A heart attack may turn fatal if your blood vessels are not opened up at the soonest possible time, or if you do not recieve any shock from the defibrillator if its VF that u're having.
cardiac arrhythmia is when u feel that your heart is beating irregularly. arrhythmia itself is a very vague word cuz there are many types of arrhythmias and they all have different severity. AF (atrial fibrillation) & VT (ventricular tachycardia) & heart blocks & AT (atrial tachycardia) & SVTs (supraventricular tachycardia of more than 3mins) are dangerous arrhythmias which needs attention.
What causes arrhythmias is a pretty challenging question even to electrophysicians themselves as there are no definite cause out yet. But it is believed that familial history plays an important part of it. Some are in the genes of one.
Dangerous and serious arrhythmias can be treated to almost near cure via an ablation.
In short, there are several diagnostic tests that u can do to help check your heart out.
Holter Monitoring = 24hrs ECG recording to see if any arrhythmia happens in any point of time in the day or night.
Stress Test = to see if u have any block arteries that requires attention. -check for chances of ischemia.
you will run on a treadmill machine like what u see in gyms, and your ECG will be monitored at the meantime to see if there's any changes to your ECG while you're running. be it your vessel part, or any arrhythmias.
be calm about it now. do a checkup first if you're worried.

Most of the time there is an underlying genetic abnormality or random circumstance and there is nothing you can do about it. You may want to talk to your doctor about your concerns though as they may indicate an anxiety issue.

You mention blood clot and arrhythmia's they however are not the same . A blood clot usually forms in the lower extremities and travels with the blood up to the heart or lungs thus the pulmonary embolus (embolism). People who have emboli most generally have undergone a surgical procedure or having a health issue, something that decreases their mobility which helps the clot to form.. Some people who have issues with atrial fibrillation can developer clots (this is a form of arrhythmia) these patients are treated with medications to help prevent their blood from being sticky enough to cause a clot to form.There are circumstances that may require the need of a pacemaker to help the heart beat more effectively. If it is a big problem a surgeon can place a vena cava filter in their groin to catch clots in the legs traveling up toward the heart or lungs.
My mother developed 2 pulmonary emboli after having surgery a few years ago. She said her feet initially felt heavy and then she felt short of breath later. I don't believe because you have a cold that you are anymore at risk for either than prior to your symptoms. Blood clots form because of decrease mobility such as laying around alot, especially after a surgical procedure. That is why the nurses are so determined to get their patients up after surgery to prevent these complications. Anytime you experience shortness of breath or swelling in the extremities with or without redness you should see a physician immediately.