Moving in a different direction.
There are many reasons why a summer internship may not have turned out the way you expected. It could be a cultural mismatch, you being driven by new interests or a slew of other reasons. Either way, take a few days to reflect on what you learned from the experience and energize yourself for a new adventure of recruiting for full time roles.
Large percentages of students end of re-recruiting, somewhere upwards of 70%. Even with a return offer to their internship, many students like to use their MBA experience as an opportunity to really explore and discover what excites them most.
As always LinkedIn is going to be a critical resource during the re-recruiting process.
Many of the tools used during recruiting are also important as well.
Leveraging your network to find people connected to your industry or company of interest is a great way to start making inroads on the full time hunt.
Always make time (1-2 times a week minimum) to mock interview with peers and career counselors to ensure you're staying sharp and are ready for the impromptu interview opportunity which may arise.