The thing with presentations is that everyone has butterflies before giving one and the only way you learn to get over the presentation anxiety is to give as many as you can. So while you havent given a whole lot already, you can still practice. Practice out loud and ask your friends and family members to listen to you and give you feedback (if you prefer). It helps if you are talking about something that you are passionate about (you can always fake your mind into believing it too) but its not required. Try to find your own way of calming before and during the presentation...you could try breathing exercises too. Personally when I give one, I think that I am in-charge for that hour or so and everybody has no choice to listen to me. I also look the audience in the eye which amazingly calms me a bit as by that time I am just gathering information about who is actually listening (and comprehending) what I say. Remember, it is very natural to go through anxiety before presentations so you are not alone in that. The best presenters have butterflies

If one has anxiety in general, it can worsen before presentations and this is also what I think worries you. As a person who has gone through this (and still go through sometimes) I would just like to say that what doesnt kill you makes you stronger. I have given good and bad presentations...but irrespective of whether it goes well or not, it is worth the experience to learn from. I hope this helps in some way and all the best. Cheers.