If I were at party … (!) . They are both kind of correct (though your tense doesn't fit your story too well), but they don't mean the same thing. Making fun of someone would be calling attention to them, possibly in an unkind way. She laughed at me. She made fun of me.

She made fun of me!

She was laughing at me or she was making fun of me. *if I was at a party

Both "She was laughing at me" and "She was making fun at me" are correct.