xxx number of reports not handled. Does this indicate that my report is very bad or has the moderator not reviewed the report?
No, I don't think your report is
very bad if it hasn't been handled yet. Depending on the report, the moderators may not be sure of your reasoning. Spam does not always have to be obvious. Generally, if your report stays unhandled for a long time, you can consider it as soft-bad but that doesn't mean you have to give up reporting.