<human>: Using a throwaway as some friends and co-workers know my username and I want to keep this private for the moment.

My girlfriend (I'll call her Claire for the sake of this) told me she was pregnant a few days ago but that her nurse told her it won't go to term. She is currently on a contraceptive injection and due to this fact we don't use condoms

Claire basically told me that she got a positive pregnancy test but that because of her contraceptive injection(she doesn't know the name of the one she is using) her nurse told her the fertilised egg won't develop. However the majority of thing I have read about the injections tell me this wouldn't be the case

Claire said her appointment went like this:

She goes to her nurse for the injection and as normal they ask her to take a pregnancy test before being given the injection, she does so and it comes back negative. Claire is then told that because we have had sex a few days prior to the appointment she will have to take another test in two weeks. She is then asked if she still wants the injection, she says yes.

Fast forward two weeks and claire's second pregnancy test comes back positive, she calls her nurse who tells her 'you won't be able to have the baby'. This is where the confusion arises as Claire is under the impression that she doesn't need to do anything, that the pregnancy will just not go to term. 
My understanding is that the injection won't stop the pregnancy (only thing I have read is that explains this is that the injection stops the egg from receiving nutrients from the uterus wall)

She won't talk to me about is as she is 'too upset' so I'm struggling to get any information from her plus the fact the last couple of weeks things haven't been great between us

I'm posting as I need somebody to explain this properly to me as it doesn't add up and I'm not sure if There is a child on the way or not

Provide a brief overview of the text.
<bot>: girlfriend has positive pregnancy test but child won't develop, won't explain the situation properly to me, leaving me stressed and not knowing if I'm going to be having a child