I've always gone on Atlantis/RSVP cruises with friends, but I did go to several of their resort vacations solo. How comfortable you will be going by yourself depends mostly on your personality and somewhat on your age.

I am shy and do not make friends easily so I did often find myself going to dinners alone, and it was indeed a bit awkward. The hosts join you to a table with other people where there is the inevitable "let's all introduce each other" ritual that gets old real fast. Most horrifying to me was the "singles' dinner" where you get to change tables after every course and repeat the whole introduction process...

Dinner really was the significant issue. Breakfast and lunch are usually very casual buffets. Other situations where I felt somewhat uncomfortable were standing alone at the bar, sitting alone in the theatre for the show.

The more young, good-looking and outgoing you are, the faster you'll make friends, and then you'll have no problem. If you're older, sagging, an introvert or a troll, you'll find it more difficult.

Remember also that Atlantis/RSVP offer a room-share option, where they'll put you in a room with another single. I've always done that and it mostly worked out well. You may hit it off with the roommate, or at least you'll likely have him as a dinner companion for the first night or two until you each make other friends.

While resorts have about 300-500 guys, a ship has a couple of thousands, so your chances of hooking up are much greater.

Go, don't worry about it, have fun, participate in all the games and events, be nice to people. You'll enjoy it even if you have an alone moment now and then.