Anxiety is something that needs a lot of help. Next time when you are presenting or speaking in public keep a ground near to your eye contact. A good friend can help you get your confidence.
If you feel like you still hold up your anxiety then try breathing techniques. It has helped most people. When you feel anxious it’s mostly because you over think everything.

I hope you find all the happiness in the world.

Hey!
It’s completely fine to feel this way while presenting something in class. We get so many thoughts while speaking as to what others will think or how are they gonna judge me and more to this. But always remember that there are also people who will cheer you up when in such a situation. So, look to them and speak or have a point marked on wall in front of you and start by staring at that point and gradually rolling your eyes in the whole class.

Say to yourself- Everyone has fears in themselves and I have this one and it’s completely normal. Why to worry? I’ll speak confidently and give my best because that is what matters. I too get tensed sometimes while speaking in front of a large audience.

If you are having anxiety because of these problems, it will pass over a period of time. But if it’s something not getting over then I would recommend to have a therapy session as it will make you feel better and the expert will help you out in the best way possible. :)