How to tell this has become something bigger

There is no line drawn in the sand, but there are markers, and they are practical rather than spiritual.

Time. If this takes an hour or more out of most days, that is the clearest single sign.

Avoidance. If you have started praying less, or later, or alone, or skipping things, because starting has become too costly.

Cost to your life. Work, study, sleep, and the people around you.

Distress that does not lift. Not a hard week. Months.

None of these says anything about your faith. They are the markers any clinician would use for an obsessional pattern of any kind, and meeting them means the thing has grown too big for reading alone.