Do the UW questions, and review them along side FA, don't do it separately. Focus on your incorrects first. For the questions you get incorrect, figure out what intermediate in what pathway you got wrong, and figure out the logic of what made you get the question wrong. Then review your corrects in each block quickly, pausing to review any corrects you "accidentally" got right. Mark all the pathways in your reading source, and systematically review the pathways as a whole at night and first thing in the morning, you will spend the minimum time with maximum retention.
For respiratory, make you memorized and UNDERSTAND each diagram in your reading source. RV, ERV, FRC, IC, etc, is a crucial one. Make it logical in your head. Same process, do the World questions, review incorrects throughly and corrects pretty fast.
It's very doable, these coincidentally are my weakest subjects on my NBME that I have been working on as well, it's about 400 questions total in the bank. If you have any specific questions on UWorld, you can PM me, and I'll try to help what whatever I have figured out.