I used to really like physics. I enjoy the theories more than working problems and crunching numbers. But being away from it for 8 years or so really hurt me when I went to take the MCAT. Now that PS score is really holding me back. 🙁
You and me both, Haemulon! Looks like we are score cousins.
OP, you aren't in any way "slow" for not groking physics immediately. I got owned by the PS section of the MCAT, even though I did well in physics I and II, the calculus-based version (I studied hard, struggled through the text, and did problems). I agree that reading a bad text with poorly explained and interlaced formulae is no fun. I did a lot of skimming. I loved writing lab reports and enjoyed the more theoretical aspects of physics (derivations, second-order differential equations, Maxwell's equations, etc.), but hated the more concrete Newtonian mechanics.
Guess what showed up in abundance on the MCAT? Yeah.
Anyway, stop judging yourself and get the help that you need. You are not your physics ability. For one thing, personal interest, the quality of the text, and being able to see how it all elegantly connects together are huge factors. Do whatever it takes to learn the stuff. Use other resources to learn the material, if the book is terrible, and start a study group where you can talk it over and reason it out with others. Dialogue often helps. Do as many problems as you can; as my physics I teacher often told me, physics isn't a spectator sport. You literally learn by doing. Reading formulae pretty much sucks universally, unless you are the type that can "see" in symbols. Manipulate and play with the concepts and formulae until you can see them in three-dimensional technicolor, Jaws addition, if you know what I mean. You'll need this ability for the MCAT.
Good luck and don't be afraid to seek help. Solid knowledge of the material is crucial for the MCAT, don't leave any stone unturned.