Hi Chloe that all sounds really painful and scary. I haven't experienced this but is it worth you ringing the nurses on here to get their views on it? It sounds like you've been fobbed off by the hospital
I have been diagnosed with breast cancer for a second time (had it 13 years ago) now other breast, I have had an mri guided core biopsy which bled quite a lot, pressure was applied to stop the bleeding, then I had to have a mamogram straight after, the bleeding started again, more pressure. It was very painful and swollen. Heavy bruising came out the next day and that 12 days ago now is starting to fade but there is still a huge hard lump that must have been from internal bleeding, I went back to the hospital and they said it should go down but it has not as yet. Still tender but not that painful.