When I was young, I had a similar problem. I really was a mess who couldn't look anyone in eye and spoke way too softly, forgot my points, and took everything as a personal criticism and was afraid that every word would cost me my job - I think you can relate. My boss sent me to a public speaking class because being able to make presentations to a hostile audience was a key part of my profession and that helped, but what really licked the problem for good was a specific practice technique.
What I did was go into an empty room and practice and video tape. Over and over and over again until I could watch the tape without cringing. Spend a couple of full days at this (on a weekend if need be). Practice your gestures, exaggerating them at first until you can settle into a comfortable level of gesturing. Try different tones of voice, different volumes. Pretend to be someone who you think does a good job at those meetings. The way people learn best is by experimenting and exaggerating things helps you move from too little to too much to just right.
The thing about exaggerating when you practice is that you know you are exaggerating and then you can relax more about it because it is supposed to be over the top. And for people who are not naturally extroverted, what you see as exaggerating in your mind, might just look polished and professional on the video. That is because we often underestimate how much we need to correct. And it is easier to back off of an exaggeration than to move away from what currently feels comfortable. I learned thing when getting coached for dressage - when the coach made me exaggerate, it was much faster to get to the exact position I should have been in than trying to get incrementally better.
One key thing is doing this is to consciously try something different on each iteration of your presentation. Do the first one and review it and note what needs to change to be better. Be mentally prepared that it will feel horrible, trust that it will get better much more rapidly than you can guess right now.
Then consciously change one and only of those things at a time until it does get better. So if you feel you are speaking too softly, the next time, try yelling, then try to move to a slightly lower tone of voice than that time. Eventually you will hone in on the correct volume. The work on the stiff gestures. Then work on looking people in the eye or whatever problems you have identified.
Yes, this is hard work. It feels awkward and embarrassing at first. Do it anyway. It will pay off because you are in a field where you need to be able to do this.
Start by fixing your presentation by yourself and then when you have gotten more confident that you can do the basic presentation well, then get someone to help you by throwing ridiculously hard questions at you as if they were the senior manager. Once you have the experience of being able to think on your feet, the real thing won't be nearly as intimidating.
