I have a PhD in synthetic chemistry, and I had to give a ton of presentations during my Phd, my post-doc, and now for my job in a drug company. I don't know, you just have to get through it! I've tried a bunch of stuff. Keep exploring and trying new things and don't back away. Don't take it personally when you have a rough day or talk. Definitely the more I speak and do public speaking the less awful it feels.