f the name on your confirmation (the one you print off - i.e. booking confirmation) is correct and it corresponds with the spelling on your passport, then you are fine
If the name on the passport is exactly the same as the one associated with the number then all is well
In general, I agree with Shelley & Vincent. I would add that discrepencies with names is a common problem at check-in.
If at all possible, contact reservations sooner not later. If this is not possible take additional forms of ID such as bank statements/creditcard statements - especially useful if they show the booking transaction. Then go directly to the customer services desk before
checking-in, they can amend the reservation details prior to check-in.