Too much school, loans, and loads of reading. I’m barely even in now, honestly. But I love it.
For basics, I’d recommend David Bentley Hart’s The Story of Christianity . It’s the most global introduction to 2000 years of Christian history I’ve read so far. Definitely worth buying for anyone interested in the topic.
The First Seven Ecumenical Councils by Catholic author Leo D. Davis SJ is a great, comprehensive history of the most important gatherings of Christian leaders in the first thousand years. He focuses a lot on the waxing and waning papal authority in these years, but that’s to be expected by a Jesuit. (That’s not a slight, just an acknowledgment of priorities).
If you’re interested in theology, you may want to read J. N. D. Kelly’s Early Christian Doctrines, which tracks the development of thought regarding dogma, practice, and organization from the 1st to the 5th centuries. Jaroslav Pelikan’s 5 volumes on Christian Tradition is also a classic here, as well as Johannes Quasten’s Patrology in four volumes.
If you’re interested in primary sources, I’d recommend the following:
Bart Ehrman’s Apostolic Fathers in 2 volumes.
Anything in the Popular Patristic Set.
Anything in the Ante-Nicene, Nicene, and Post Nicene Fathers Sets.
For audio material, I would suggest this podcast by Dr Jeffrey Macdonald, titled Orthodox Church History. Though his focus is on the tradition and development of the Eastern Orthodox Church, he spends a great deal of time going over the shared history between all Christian denominations leading up the the Great Schism in 1054AD.
If you need anything else, let me know. :)
EDIT: I should mention that some of these books might be available at some libraries. They’re definitely available at theological libraries in seminaries.