Hmm.
Having seen a few white-collar layoffs in my time, a vague promise to interview you for other positions after 6 weeks is really not worth a lot. If they were serious about shifting you somewhere else, your line manager would be out shopping you to other business units now. I hope that he/she is, because you need someone testifying to your skill and usefulness to get back in the door.
Think of your reputation as a depreciating asset. After a month and a half, your IOUs and goodwill, carefully built up during your time on the job, will be worthless. Your client and customer relationships will be worthless. Don't take that sitting down.
Talk to HR about the details (and don't forget to ask if 6 weeks is the best they can do - likely they have discretion to offer a couple weeks more and occasionally a whole lot more than that), negotiate a formal last day after you've "used up" remaining vacation and sick time rather than having it paid out as a lump sum (which should give you a couple weeks of paid job hunting while still on the books), ask for internal interviews to take place before your last day, rather than after. Try to negotiate continued access to the internal-applicant system, especially if you're at a large corporation, for a set period of time. Most importantly, leave gracefully. Your last impression is your lasting impression.
Then assume that once you're severed, you're done. Start living off your war chest (spending as little as possible, cutting expenses to the barest minimum) and start pounding the pavement immediately (clients, colleagues, etc), even while you're still showing up at your current job. Give yourself a weekend to get over it, then you have a new job: 8 hrs a day, minimum, finding a new gig.
