This isn't an either-or decision. It's a which-first decision.
Or, maybe you can do both at the same time; in the sense that a student takes more than one course each term.
You didn't say how much programming experience you had before starting PHP/CodeIgniter. There's a lot to programming that's not specific to any programming language or framework, primarily the ability to look at a problem, divide it into manageable sub-problems and write reasonably efficient code for each--code that another programmer (or *you*, after a year or so) can read and understand.
And you'll probably be learning more about those for your whole programming career. There's a lot to learn, it's not all in books or "tutorials", and "what's important" changes over the years.
For now, learn to use CodeIgniter to create a couple different types of web apps from the drawing board to a site you can show off. Then maybe look at doing the same with Joomla or Drupal or something. Or plain PHP. The point is to take a look at the same types of problems from a different point of view based on what your tools support.