Hey darkknight, NJ native myself. I can certainly relate to your uneasiness with combinatorics/probability problems. While the underlying theory never changes, the methods of application are wide ranging and sometimes dependent on very minute variations in wording (and thus implied meaning). I never found just one resource that did it all for me (not saying that one doesn't exist though!), but here's my suggestions:
1) GMAT Club Free Math Book - there's a section on combinatorics/probablility that you should really work hard to read and understand
2) Veritas Prep Statistics & Combinatorics - problem set that starts off easy gradually gets harder
3) Karishma's Veritas Blog
https://www.gmatclub.com/forum/veritas-prep-resource-links-no-longer-available-399979.html#/?s=comb ... cs&x=0&y=04) GMATClub quant section's combination/permutation/probability/counting problems and more importantly, their solutions and explanations that are all consistent and fundamentally sound (via Bunuel/Karishma)
5) Google search on theory (I remember watching a Khan Academy video, although it was very basic in nature, maybe a good place to start?)
Good luck!