Is My Dog On Heat Or pragnant ?

My Puppy Has been bleeding from the l area & we hav had dogs hanging around (but thy hav been 2 big 2 get in heh heh heh ! ! ) anyways, today i went out the yard 2 feed & play With the animals & there was a lil foxy x jack russel in the yard ! ! it was defiantly trying 2 get on with Fee Fee (The Pup) I bought her & her sista in immediatly i think tht his still out there O.o lol, so is she on heat or pregnant ?