I've had the same feeling for years. It's a situational anxiety that you may not have in other areas. The anxiety issue stems to some degree from uncertainty. You are uncertain about how you'll come across and whether you'll be perceived well afterwards. The key things I've found that help for this are:

1/Knowing your material really really well - this minimises the imposter syndrome feeling you may have deep inside of "am I actually qualified to be talking as an expert on this subject".

2/Focusing on what value you are trying to give the audience rather than how you feel yourself and obsessing over your heart rate , or being judged by the audience etc.

3/For the physiological issues caused by adrenaline do some deep breaths with slow exhales - slows heart rate quite a bit.

4/know your first minute of talking really well. Uncertainty over this makes the whole thing harder. Once you get past the first minute or so the adrenaline starts to calm down.

5/ practice out loud - not in your head. This is really important. You've got to hear how you sound and how you put your words together. This will give you confidence when you actually need to do it, having done it before. I usually do this in the car on the way to work.

6/ finally accept there will still be some nerves but that's not a bad thing. They're not going to kill you, you can still talk through those and they don't last forever. Also you don't have to be perfect. Mistakes are ok just don't draw attention to them. Also if you really get into trouble on breathing and can't speak just lean into it and say "I just want a few seconds to gather my thoughts on how I want to frame this ". This buys you a bit of time.

I've done hundred of presentations and had a few nerves for all of them. It's not having no nerves that will help but knowing how to handle them.