I cant get enough air

Even though I appear calm, I don't feel like I can breathe adequately. I feel pressure in my head and it feels like something is sitting on my heart. i feel a bit dizzy. But it's been 4 days without interruption. In the past, it used to take 1-2 days and even took 10 days. I don't understand if the reason is anxiety. Its not too intense im able to handle it. I do not have any other physical diseases, I do not have asthma