"lo siento" explanation

Hello, I'm a beginner Spanish student and just yesterday I got to direct/indirect pronouns (lo, la, me, te).

I understand what "lo siento" means (I'm sorry), but I'm just confused as to what/whom "lo" (him/it) here is referring to? Can someone please translate/transliterate/explain the purpose of "lo" in this phrase?

Does this transliterate as "I am sorry for it" ?

Thank you!