Public speaking anxiety is
normal.
It is a natural response. The only way to overcome it is to confront it - ideally
without drugs.
I have done a lot of public speaking; as a musician, lecturer, tutor, student, being interviewed on radio and tv - as well as jobs i've had where i've had to make PA announcements, address groups in work meetings and train/induct staff - all that kind of thing.
It used to make me very nervous, but i've learned to overcome a great deal of that fear.
You're young dude - this is one of life's valuable learning experiences. Drugs won't solve it.
Trust me; you're more likely to have an awkward/embarassing/unsuccessful public speaking experience if drugs are involved.
I speak from experience there, too.
Over time i've found the slight adrenaline jolt i get from apprehension to be somewhat performance-enhancing in itself.
The fight-or-flight response doesn't inevitably cause you to fuck up; it can have the opposite result too, and increase your ability to think on your feet. Like a natural stimulant, if you are confident and informed about what you are speaking about.
Obviously this can be hard as a student - but it's part of the learning process and getting a well-rounded education.
When i'm playing music onstage in front of an audience, i can achieve a level of focus that feels (albeit very subjectively) to improve my creativity and focus. Speaking can be a bit different, but honestly - it's a very valuable skill to have in many parts of life for some people (myself included).
Taking drugs in an attempt to get through the experience is counter-productive in the sense that you might cheat yourself out of a valuable learning experience.
Just remember that virtually
everyone finds public speaking daunting - and this is partly because for most of us, it is something we rarely have to do. But it
does get easier over time.
My motto when it comes to things like this?
"
Fake it 'til you make it"
I should mention a couple of other things though.
Firstly, we don't really allow threads where people ask "what drug should i take?"
And secondly, Xanax/alprazolam - and
any benzodiazepine addiction - is nothing to take lightly. I leatned that one the hard way too. Benzos are very dangerous for addicts, because withdrawal can cause very serious reactions such as seizures, psychosis and even death.
But even without getting addicted, drugs like Xanax have a terrible tendency to make us act erratically - lowered inhibitions, lack of physical coordination and balance, amnesia/memory loss and (in higher doses) things like slurred speech.
Any and all of the above can result in an absolute trainwreck of a public speaking disaster.
Even if it works for people, they can then become (psychologically) reliant on drugs to ever speak in any sort of public situation.
That's really a good way to
confront your fear - which frankly, is something you will have to do if you wish to pursue a pretty wide range of academic or professional paths.
If you know your subject well, prepare yourself - make "cheat sheets", "palm cards" a "script" (of sorts - preferably with dot points) - you can get through this. Drugs will actually make it harder.
With adequate preparation - and a bit of bluffing - you can fool people into not even realising you're nervous.
But even that doesn't matter; if you're a junior - there's nothing wrong with being nervous, so if it is troubling you - just admit it to your audience and get on with whatever you have to say!

It's perfectly normal to be nervous; but with a bit of work, you
can overcome it. And if you can do that, you've taught yourself a very valuable (and marketable) skill.
It used to make me feel physically sick having to speak in fromt of people, but I've learned to
enjoy public speaking. It can be a great feeling, and very rewarding in a number of ways.
Good luck - you can do it, and you don't need drugs to do it well.