Constipated Kitty

i just got a new kitten Wednesday. I found him/her struggling to walk after what i think was getting hit by a car. i couldnt leave him there so i grabbed him. he couldnt stand and everytime he tried his leg would give out and he would fall over.luckily his leg isnt broken and after a day he can now walk. 

but new problem. he pees blood. not thick blood but watery. and he hasnt pooped or peed normally in over 36 hours. todays friday and he hasnt gone since at least Wednesday.

he was trying today but all he does is pee a little watery blood.

i dont know what to do.

The kitten should be taken to a vet immediately to be checked for internal injuries. This isn't something you can handle yourself - he really, really needs professional help. If you can't afford to take him to a vet, please take him to the nearest no-kill shelter so that he gets medical attention.

Yes, absolutely take him/her to the vet now.  He could have an injury affecting the way a cat defecates.  Very bad things happen when that occurs; learned that the hard (fatal) way.