my little girl was jumped on and shes not even 1 yet so i took her to the vets and got her the morning after injection,but her tits are big and now i dont no if the jab has worked ,how do i find out if she is pregnant befor its to late

Take her to the Vets to have he scanned.  they can be given an injection right up to 6 weeks from mating to abort the pups if the bitch is needed for future breeding, or she can be spayed if found to be in whelp and it isn't too far along.