Where did this saying come from?
Such is life, and every day is getting sucher and sucher.
It doesn't make any sense to me, perhaps because I'm not a native English speaker. Can someone explain?
That's the sort of thing one says when Murphy's Law rears its ugly head. Something has gone according to plan -- just not your plan. You know the sort of thing: you finally found that classic '50s roadster to restore, and ten minutes after you purchase it (and before you've managed to get it insured) a bull moose decides that it's a potential rival for the local really hot cow's romantic attentions and batters it into a heap of twisted tin foil. Sometimes life is like that.
Sometimes life stays that way for an annoyingly long time. That's the "sucher and sucher" part. No, there's no such word as "sucher" (at least not in any recognised sense) -- it's just a way of extending the "such is life" cliché to meet the ongoing run of rotten luck. People understand that "such is life" means that you've had one bit of bad luck, and they can read the "sucher and sucher" to mean that it just keeps going and going like the Energizer bunny.