Students have no respect

Okay so I tried to tell some of the stuff that we’re going to do letters with me, they looked disappointed and said, “Awwwwww”
And “No!! I don’t want to do it with you!!” “We want to do it with Mrs (her name).”
So when I went on with the lesson, some were being disruptive and rude to me. I asked who wants to try and none of them wanted to do it. One was like, “No!”
“Don’t look at me. I won’t say it to you!”
I was just having a hard time. The teacher said, “Just be FIRM. They need to do it and you’re the teacher.”
I tried too but they left and ran around. I looked at the other teachers and they just gave me that “Oh well” or “I’m not helping you” look.
It was the worst. After the lesson, now I’m emotional and about to cry. It is like ever since I’ve gotten so strict and more stern they don’t respect me still. They’re more scared of me. Mrs (her name) is stern but the students love her. What am I doing wrong? Even the two students that respected me didn’t want to listen to me and yelled hurtful things to me. 😭😭😭😭