How did you calculate it? Does your university have a classification calculator that tells you, or did you just add it up yourself?
I don't know what university you're at, but a lot of them have incredibly odd systems for calculating degrees, where some modules are weighted differently depending on which year you did them, some modules won't count at all, and some carry more weight despite supposedly having the same credit value as others. Some universities take the mean average of your module results (after weighting), and some take the median, which can produce two different results if you're borderline. Unless you have actually used the university's own algorithm, I wouldn't bank on anything yet.
If you're very borderline, you may also be given something called a discretionary mark. This is more common on the 2:1/First border, where if you got, say, 68% or 69%, but achieved a first in a certain percentage of the core modules (again, determined by the universities weighting algorithm), they will give you a First, even though you technically get a 2:1. This can happen at any border, though, so you could be in line for a discretionary 2:2.
Just don't even think about the mark until you have the actual results.