Post-bacc rejections, interviews, and tes-taking

I have been applying to two post-baccs near where I live (there are only 2 that I felt were worth applying to, perhaps a mistake on my part since there are five in this area).
I received a straight rejection from one, while I interviewed with the other last week.
The interview went okay, however, my general impression was that I talked too much and that in hindsight I probably won’t get accepted. Oh well; there are other options.
During the interview, however, one of the interviewers, a chemistry professor, brought up the issue of apparent problems in test-taking. He could tell that while I appeared to know my sciences, I could not regurgitate and synthesize the stuff on a timed test. And he was right. In looking back over my less-than-storied academic career, the major problem I have had has been one of not being able to think fast enough to finish a test, even when I did “know” the material.
Does anyone have any ideas on how to improve this? I have tried doing endless problems and practicing writing essays, but still get frustrated with the time issue. I wish there was some way to THINK FASTER AND CLEARER during such strenuous episodes.

You may want to consider getting evaluated for a learning disability, since this is a classic problem of folks with certain kinds of learning disabilities. Learning disabilities don’t mean that you don’t learn and often have nothing to do with intelligence; they affect how you process information. So, it may be that you can get around processing problems when you have more time, but the compressed time exposes these processing problems. Diagnosis of a learning disability might get you extra time for some tests, as well as help you better strategize how to get around any challenges even without extra time.
Alternatively you may want to consider whether test-stress is the real issue–that is, anxiety might be driving your inability to demonstrate your knowledge–in which case working on this in a behavioral therapy setting might be helpful. Either way, it sounds like your case may be specific enough–test-taking problems and not knowledge or studying problems–that getting some thoughtful professionals to help localize the problem may be very helpful. The paradox of this is that you are more likely to be able to get this help if you are enrolled in an academic program with these kinds of support services present on campus. Otherwise it may require an outlay of cash, although some health insurance policies may cover the therapy aspect of it; probably they won’t cover the learning disability assessment.
Good luck.

I would think the only way to improve on such issues is to practice after practice even if you think you know the material.