Perhaps my main advice is to stay calm and professional throughout the discussion with BU. It is also likely that the person who you will be talking to might not have the authority to give you more on the call, but might just listen and perhaps get back to you later.
To me it seems very likely that you will end up needing to stay where you are (which I understand is GWU) for financial reasons – and that is fine. You are already at a good university in a very marketable major.