The Creed was not included in the Sunday Mass. Did I fulfill my Sunday obligation?
The only allowable reason to omit the Creed at a Sunday Mass is if baptisms are taking place and the baptismal promises take the place of the Creed.
Otherwise, the Creed is always to be included in a Sunday Mass (GIRM 68).
To omit the Creed is illicit, but its omission neither invalidates the Mass nor the satisfaction of the Sunday obligation.