I am giving a presentantion in couple of days. I need help!

I am giving a presentantion in couple of days. I need help! I am having a presentation in couple of days and in need of a help. I don't stutter when im with my friends or family but when I need to say or give a presentation to the whole class I feel like my voice is blocked. I don't repeat word, my voice just get's blocked when I start to read a sentence. Can you give me some tricks to help with that? Thanks <3