The Feynman lectures on physics are now available to read online for free. This is a classic resource for not just learning physics also but also the process of science and the mindset of a scientific rationalist.
Actually, this was my experience, as well. But I did not truly learn the subject until I used a more standard text (not Giancoli, but similar). Feynman gives you ideas and intuition, not mastery.
The Feynman lectures on physics are now available to read online for free. This is a classic resource for not just learning physics also but also the process of science and the mindset of a scientific rationalist.