Would soffit vents cause a house to be more drafty in the living space?

I have an older block home with siding. The only insulation in the home is in the attic floor joists. The home has two gable vents. It is also built with that breathing space with firring strips between the block and drywall. This space runs from the attic to basement. I vented the soffits by nothching out the wood and adding vented soffit siding, cause the house had no vent holes in the soffit at all. My concern now is that in an attempt to make the attic cooler, I actually made the house colder and harder to heat in the winter. Any opinions welcome.