I feel like I am going to die of suffocation whenever I speak in front of my cl.?

i have a presentation to do and it's pretty long. in the last few years whenever i get up to speak my voice shakes and my throat like closes in on itself and i can barely speak. it sounds like im going to cry haha...not funny actually. also my adrenaline goes crazy. this happens even sometimes when im called to read a paragraph from a book we're reading or discuss a question. im actually a pretty cool person when it comes to communicating like this public speaking thing is not like me and it's ruining my happiness in these cles. is there anything i can do other than give myself a peptalk or something like that to stop these mortifying things from happening? i want something effective!