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Hello good afternoon, so ever since the beginning of this month I’ve been experiencing dizziness, first I can’t seem to inhale air and when I try i can’t inhale through my nose like if something was blocking or preventing me from inhaling, but after that goes away after a few seconds I can inhale fine. After I can’t inhale for a few seconds, about 5 seconds later my head starts feeling tight and my vision sort of goes away like blackness is taking over my vision. It only lasts for a couple of seconds and then I go back to breathing in and seeing normally. It’s happened twice this month and whenever my vision starts to darken I fear that I might be dying, what might be the cause? Please help