I'm about to take a solo cruise myself in a couple of weeks.
One thing that is great to do, is certainly sign up for forum groups like this one (and perish the thought...there are OTHERS), and you can register on the ROLL CALL for your ship. That way you will make and meet instant friends for once you are on-board!
As mentioned, the Norwegian EPIC has singles cabins. However, if you don't mind a lower deck inside cabin, even if you have to pay the double fare, it's really still pretty affordable. And if you are like me, you are only in your room to shower, sleep and change clothes. You WILL have to pay the double occupancy fare on those ships, but you WONT have to pay double the taxes, port fees and resort or tip fees. Also Norwegian often offers 100 or 150 specials....where as singles only pay the one far or one and a half fare. Call them and ask a Cruise Consultant what itineraries are offering the single supplement deals. Frankly, given the economy...I'd call all the cruise lines and ask. Can't hurt!
Have a great trip!!