‘Personally, I'd have welcomed a dementor attack. A deadly struggle for my soul would have broken the monotony nicely. You think you've had it bad, at least you've been able to get out and about, stretch your legs, get into a few fights.... I've been stuck inside for a month.’
Harry Potter and the Order of the Phoenix
"have(got) it bad" means to be very much in love according to Cambridge. It doesn't seem to fit for this particular context. However, that's the only meaning I found in dictionaries. How should we understand "you've had it bad" in this context? In my opinion, it can probably be paraphrased as "You take it as a bad thing for you."