A brother told me it is not allowed to say “I’ve had a bad day/week” because it falls under insulting time which has been prohibited. I told him I don’t think that’s the case but I’ll ask about it. Would this be insulting time or not?

Ustadh AbdulAziz al-Haqqan

No, if you only mean that the day was hard, and Shaykh Ibn Uthaymin said it only becomes prohibited when the intent is to blame or curse the day itself.