Selling problems...

Having got all excited at finally having a publication date for my second book, I have now discovered a problem that needs sorting before that date. I had no idea that my book is currently unavailable in the US - why when it is easily available through Amazon UK, etc? I think I need to discover an easy way to sell my book online myself (besides through my publishers), perhaps through my website.
It's soooo frustrating! Nothing ever seems to be easy.