Good job! I made some revisions. There are many ways to write this.

Recently, I started watching a romance drama my friend recommended to me. I didn’t think I would like it so much, but now I can’t stop watching it. The story is so sweet, and the characters are really nice. I want to see what happens next!

"Recommended to me" is correct, but native English speakers often say: "Recommended me", so that's fine honestly. Overall, it's a great thought, but you could improve "sweet" and "nice" for descriptive language. Sweet how? What makes them nice?