What does it mean if you got backpain in your lower back and bleed a little bit after you've pooed?

You didn't say if there was a lot of blood or just a little after wiping, so I'll put this out there in the event it pertains to your problem. If the blood is a bright red color, the bleeding could be due to straining while eliminating or even from diarrhea. Both conditions sometimes cause hemorrhoidal irritation (which you could be unaware of even having) as hemorrhoids can be internal as well as external or both. The bleeding occurs when the tiny veins on the inflamed tissue, either surrounding or within the rectum, rupture (or burst), and it's this bright red blood that you're seeing on your toilet tissue. Please keep in mind that I am not a doctor and you should seek professional treatment if your condition persists or worsens. Also be aware that if the blood you're seeing is not bright red but black or a darker color, you should see your physician immediately!