I think the pregnancy was to hang on to you and when in fact it did not work and suggested a pregnancy test, she panicked and had to fabricate a story. My guess. She was not in the ER at all. Blood in the urine would be a possible UTI, not signs of miscarriage. You been had. IMO
bez, I agree the timing of this is exceptionally suspicious.
On the other hand, you were breaking up anyway. Had you had an accidental pregnancy you would have to deal with that somehow - I think she will end up actually pregnant this time if you get back with her.
I would say, honestly, that if you do in fact decide to "make another go" of this, demand proof. Demand her emergency room visit summary receipt.
If she's telling the truth I would think she would have already waived that in your face in anger. If she's lying, she'll at least have more respect for you than to think you're a patsy.
How would you know if she was lying? I would say if you question her now than there is no point in trying to work anything out. Relationships are built on trust of which you don't have much for her.