YOU SAID:

Laying my head on my pillow I realize my sister isn’t here though she said she would be.

INTO JAPANESE

枕に頭を置くと、妹はいると言っていたのに、ここにはいないことに気づきました。

BACK INTO ENGLISH

When I put my head on the pillow, I realized that I had a sister, but I wasn't here.

INTO JAPANESE

枕に頭を乗せたとき、妹がいることに気づきましたが、ここにはいませんでした。

BACK INTO ENGLISH

When I put my head on the pillow, I noticed that I had a sister, but I wasn't here.

INTO JAPANESE

枕に頭を置くと、妹がいることに気づきましたが、ここにはいませんでした。

BACK INTO ENGLISH

When I put my head on the pillow, I noticed that I had a sister, but I wasn't here.