hey there and welcome to pc.
i'm sorry to hear you've been feeling so terrible.
what youre experiencing sounds like panic attacks, and i thought you should know that while they are very frightening and overwhelming, you are most certainly NOT going to die. that feeling that youre being tortured, its horrible and i can totally relate.
there are a lot of different things you can do to try to gain control when this happens. breathing deeply in through your nose and out through your mouth will help slow things down a bit. i try counting my breaths because it keeps me focused and slows my mind down. for some people it helps to keep themselves occupied when they feel the anxiety creeping up on them. sometimes you can distract yourself enough that it doesnt turn into a full blown panic attack. you could read, watch tv, or go outside for some fresh air.
have you ever considered going to see a doctor or therapist? sometimes talking to a doctor helps you to understand it better. there are also a number of medications that alleviate the symptoms.
hope this helps a bit. best of luck and feel better soon.