It probably got forwarded to the kickstarter email address.
If you got the conformation from Paypal, it should be fine. Within a couple weeks the reward management site and Paypal mailing list will be set up. Until then, there is no point in looking up individual transactions, since the backer site would need to be finished before problems could be fixed, anyway (in the unlikely event that something went wrong with the transaction despite Paypal's conformation).
