So I was able to email the third-party website I made my donation through, and they'll give me a refund. That should settle everything, if I understand correctly. I'm so relieved.
So yeah, I'm an idiot. I've learned my lesson and from now on I'll be very careful.
While it's illegal for you to donate money, my understanding is that you can volunteer for the campaign if you so desire. (Not official legal advice, so maybe check this first.)
That's definitely true. I remember in 2006 I did some campus lit dropping with some students who were visiting from Sweden.