International Prescription Help? Vyvanse

I recently left the US (Michigan) and came to the UK to study abroad. The term here is less than 6 months, so I am unable to receive the UK's universal health care. My pharmacy told me that it would be able to ship my Vyvanse (30mg) over here, but now it's telling me that it can't. My parents tried sending my Vyvanse through the mail, but it was stopped at UK customs. I don't know what else to do.

I thought about seeing if my health insurance from the US would pay for a visit to a UK doctor and for a prescription of Dexedrine or something (Vyvanse hasn't been approved over here yet), but even if I did that, I'd probably have to be rediagnosed with ADHD.

Can anyone think of a way out of this? There's no way I'm going to be able to pass my classes if I have to go through amphetamine withdrawal. I find it odd and incredibly simple-minded that I can take my prescription with me on the plane but I can't have it shipped over here.