To agree with bohm, I had an Iranian quantum mechanics professor who said in his experience, Westerners have a more difficult time grasping QM because our culture biases us towards causality and concrete ideas, whereas Eastern thought is based more on abstract ideas.
QM is very counter-intuitive and has few classical analogues to make it easier to learn without dumbing it down so much you lose what is really going on. Re-reading difficult to understand passages several times, and looking to a little outside research may help you as it helped me when taking the course.
Another thing to keep in mind in your reading is to keep your ideas of QM and M-theory seperate. As far as new theory, the core of QM hasn't been an emerging field in a long time, though many of it's practical applications have just come into use in the last 2 decades and many are still waiting to be invented or become feasible. QM could be superceded someday as just a special case of another, more encompassing theory, but the important thing to remember is that QM is very refined, and it works.
M-theory, on the other hand, has a lot of support in the scientific community as eventually leading to the best understanding of the nature and structure of the Universe, but it's going to be some time into the future before enough testable evidence is obtained to see if they're on the right track or if this is a dead end.