How do you include headings inside same page in the TOC?

[Animeshz]

I tried to do this while writing a 0.75 aspect ratio document, and I seem to have 2-3 sub-headings in the same page and the Toc only renders the first heading in the next page, and if there's none in the next page and everything's got covered in the same page then it shows no subheading in the Toc.

Is there a way to include the subheading in the same page too?