Can you give me confidence for my upcoming speach?

I'm running for freshman class president. Im new to the school so not all the freshman even know I exist... I signed up for class president because no one signed up for the position and the last day to sign up was soon after. And I just wanted to be involved in school. I don't really care if I win or not, I just want a great presentation as my first impression to others.

But now I got 2 girls who are also running. So far, none of them have advertised their campaign. And on Thursday (2 days from now) we present in front of all the freshman.

I've been talking to different people in my school in different grades and they all gave me good advise. Like eye contact and speak clearly, but I need more of a pep talk.

When I present I'm usually a confident speaker if I am confident in my work. But they gave us such short notice about making the speach.

I'm comfortable talking infront of groups up to 30 people, but I've never presented infront of 150. And I'm usually shy infront of people I don't know. It was too late for me to back out and I saw my competition and they seemed like average people (I mean like not Queen Bee of the class).

A part of me is scared and wishes to get sick that day, but another part of me sees it as an opportunity for a learning experience and to put my self out there and actually have those in my grade level know I exist (I've got only 2 classes with freshmen)

So I need a pep talk and advise on what to put in my 3 minute speech.