Sudden increase in heart bpm

I'm a 16 yr old male.
I've been experiencing this once in a blue moon since middle school I think.

It's usually occurs when I forcefully swing my right arm across my chest from about shoulder height to anywhere on the left side of my body. My symptoms usually vary depending on the force involved in swinging. Normally this occurs when I'm playing American handball or tennis and the symptoms that accompany it (which occur all of a sudden) include a feeling of fatigue on the sides of my throat, fatigue in my gums, increased breathing, strong thumping under my sternum (which I think is just my heartbeat), and sudden feeling of tiredness. However, a few weeks ago, I went to the park to play handball and I experienced a more severe form of these symptoms. I began experiencing mild hearing loss, headache, severe vision blackening (like a shroud of small black dots slowly blocking out my vision and making it difficult to see), and more surprisingly, loss of balance. I fell down, sat for a while, and as I got up to get a drink of water, these symptoms gradually disappeared and I was left with a slight headache after the drink.

I don't recall my bpm but I think I had around 3-4 beats per second (and I could really feel my heart pounding at my chest).
The only person that had a heart problem (that I know of) was my grandmother who died from a heart attack.

Does anyone know if I have a condition that is causing these symptoms? Thanks.

Clearly, you have a family history of heart problems, and any symptoms like these need to be checked out by a doctor or medical clinic immediately.

I would not engage in any behavior that has or can be expected to produce these symptoms until you get medically checked out.
Good luck.

I agree with Kirk C. It sounds like it could be a heart issue, and you really need to talk to a doctor about it before you do anything else. When can you see a doctor?