Ok, glad you are breathing again...but definitely don't stop till you have an answer.
You have extensive family history of cancers, which may be coincidental, or it may be related...either way, it is crucial information and is more reason why the doctors need to take you very seriously.
My advice is to document anything unusual so that you can be sure to report all symptoms to the doctors, without forgetting anything. If the leaking starts again, consider saving the soiled garment or pad in a ziploc baggie in the fridge, it should stay moist for a while and maybe it will give them some clues.
It may be nothing at all, perhaps a burst cyst. However, you are doing the right thing by getting it checked out. Get copies of your reports for your records. Be your own advocate and don't stop till you have an answer that is based on sound evidence (not just a hunch).
Keep us posted...