That's very unlucky, it is difficult to advise you with a) no personal experience of this situation, and b) not knowing what you have been told by your doctors.
Umm generally, I would try think up any questions you still have, then try to speak to a doctor again, and get them to write or type you a document about your case (or if they won't, then go slowly and you make notes).
This would be for you to read when you want to (because it is difficult to take in information in just one conversation, especially one involving really bad news) and you could also then show this to your family when you are trying to explain what is happening.
I expect (if it was my family) they will have a lot of questions, which could be exhausting for you. As well any emotional reaction they might have. It might be better to briefly inform them, give them your document, and just leave the room for a little bit. ? At least that is how I would consider handling this situation.
You can't really not tell your boyfriend or your family. I'd imagine they will ultimately find out, and it's probably going to be awful for you and for them. But at least if they know sooner you can get past the telling them stage, and then everyone can start pulling together to get through this.
As for dropping out of uni, I would discuss that with the doctor. I'm not going to make any comment on your prognosis (because that is for your doctor to comment on) but at least I will say that I wouldn't leap to the conclusion that you're going to die or have no future.
I would also ask your doctor or anyone else that would know if there are any groups or charities for dealing with this type of cancer that you could join or could help you.