alot can account for this. not only knowledge acquired before solving the questions but also your mood and strenght(energy), concentration level etc.
you should not be depressed at all. just make sure you give more attetion to your studies and you should realize that some of the ones you got wrong could have been answered rightly
Take a deep breath and relax. Now, try and figure out if your UW scores are too high (are you doing Random timed unused question blocks?) or did something happen to interrupt you during your NBME? (NBME scores too low) I suspect its a combination of both.
You should go back over your NBME results and see if you agree with their assessment of the areas in which you are weak. In any case, go over all the "below average" performance areas and see if you can figure out what went wrong.
Then, I'd finish UW completely and then go over the mistakes you made in UWorld. Make sure you understand the explanation completely for every question - both the ones you got right as well as the ones you got wrong. UW explanations almost always have something to add to your knowledge base, so I'd strongly recommend absorbing that.
After that, pick a whole day that you can dedicate to this and do 3 random timed UW blocks in the morning and then NBME form 6 in the afternoon. That will help you determine your actual score. If it does not substantially improve, you will have to look at going over bigger resources like Kaplan again in order to guarantee a pass. I think you'll be pleasantly surprised though
I believe that the most weight goes on to NBME forms regardless of UW self-assessments. Moreover, sometimes I think that UWSA tends to overestimate performances. If you definitely want a score >90 you should work a bit harder to be absolutely sure!
Myself, I was doing 65% UW Qbank and then form 7 showed 440, even though most people said that a 65% in UW is definitely a 99. My advice is to have trust on the NBME score, and push as hard as you can. Do an NBME 1-2 months later to see how you have improved. Me, after a 1,5 month of hard study I ended up with a form 3 of 570.
Aftr enough preparatn, wht i hv learnt that always relay on nbme. Its nt 4 yr score prediction( as every1 says). Its only 2 make u realize yr gaps in preparatn. In my case, i was quite gud at uw (67%), bt whn nbme came 1st time, i was 2 tensed as i didnt knw many things. I improved myself by doing more & more nbme forms. It helped me a lot. So dnt b depressd by nbme scores, take them as study material.
Believe me, real exam is nt like nbme 1 to 4. Its more like 7th. Go 4 it aftr full preparatn.