Most Campbells in Ireland are descended from Scottish Presbyterians who settled in Ulster (and some other places) in the 1600's and 1700's. I wasn't sure from your message whether you know your Campbell ancestors to have come from Donegal. If so, then their origin is likely to fit that pattern.
However, given your own surname, it seems possible that your Campbell's might have been Catholic. There were some Campbells who migrated to Ireland before the Reformation. They came as what are known as "gallowglasses", or foreign mercenaries (from various clans) who were brought to Ireland to fight for one chieftain or another in his battles with other chieftains, and they frequently settled down and left descendants. The original Irish from of "gallowglasses' is "gallóglaigh", meaning "foreign fighters".
A significant number of the Catholic Campbells who came as gallowglasses settled in County Mayo, where I have Campbell relatives myself (two of my grandparents grew up in eastern Mayo). The following site has a map showing the distribution of the Campbell surname in Ireland: https://www.irishorigenes.com/campbell
You have to click on the little map image inorder to enlarge it so that is becomes readable, and you can download the map in its enlarged form. As you'll see, there is a major concentration in Ulster (mostly descended from the Scottish settlers), and a secondary one in Mayo and neighboring areas (mostly descended from the gallowglass incomers).
I've done DNA testing, and so has a Mayo third cousin whose mother was borrn a Campbell , so if you have been tested as well, I'd be happy to compare results and see whether that might indicate that your Campbells originated in Mayo.