I had my green card interview through marriage last week and the officer said they needed to review the case further. I did not get approved on the spot. Should I be worried that something is wrong

Not being approved immediately at the interview does not necessarily mean there is a problem. Sometimes officers need additional supervisory review or time to finish background checks. Many applicants receive approval notices days or weeks after the interview even if the officer did not make a decision that day.

It is fairly common for cases to remain under review after the interview. Officers sometimes take additional time to examine documents or finalize the case in the system. Unless you receive a request for evidence or a notice of concern, it may simply be part of the normal processing timeline.