You need the physical visa in your passport in order to return to the U.S. Cruise line may not allow you to board if you don't have the appropriate visa to return to the U.S. You should consult with an experienced immigration attorney to discuss your options.
Talk to your foreign student adviser and ask him/her if 'visa re-validation' applies.
Don't leave the US without talking to the foreign student adviser.
PROFESSOR OF IMMIGRATION LAW for over 10 years -- This blog posting is offered for informational purposes only. It does not constitute an attorney-client relationship. Also, keep in mind that this is an INTERNET BLOG. You should not rely on anything you read here to make decisions which impact on your life. Meet with an attorney, via Skype, or in person, to obtain competent personal and professional guidance.