@Vampyhooch - it's no wonder you have anxiety and depression. Those are very traumatic experiences; completely understandable why you are feeling this way.
It makes one nervous when the body takes over; be it an illness, attack of some kind, (including anxiety). You feel so out of control and possibly that your body is working against you. Not a nice feeling but glad to hear it was just a scare and all is ok now.
I'm sorry to hear about your grandad and your cousin's boyfriend too. My condolences to you and your family.
I can only imagine how petrified you must've been when your DS had those episodes. Every parents nightmare when something frightening happens.
Have you had any counselling? And I would recommend hypnotherapy.
In the height of my anxiety, my fears went haywire. I've always had a worry about choking..me or others because of a little boy I knew choked on a grape and lost his life. This was about 25 years ago but it's stuck with me. So I started watching my DH and DD like a hawk when they were eating in case I needed to jump into action. If I could've done, I would have told them not to eat at all! But in my head I was wishing that they wouldn't eat. I also ate tiny little morsels of food so I wouldn't choke. Then I had some hypnotherapy and began to see reason and become a bit more rational with my fears.
I know yours is different because you've actually lived through these terrible events but it may help you.
Ok so you have the feeling of dread today; can you take some time out and do some meditation? Maybe get out in the fresh air for some exercise? Talk to someone? The groggy feeling is normal. Some people also report feeling hot but I didn't feel that way.
Try this...interventions for anxiety by Mark Tyrell. It's in podcast form and if you scroll down, there is a video too. Let us know how you get on. We're all here for you! 
www.unk.com/blog/podcast/036-behavioural-interventions-for-anxiety/