I know it's hard to relax, but try to. They really would have to have a damn good reason to refuse you, and even then you can appeal. Like others have said, they may request further info but I've never heard of an outright refusal.
If it helps you to know, we had two Fiancé visas (they were single entry in 1998) and two Spousal visas as my hubby had trouble adjusting and went back to the US for 18 months. We got the second one no problem.
HTH