This test can be frustrating.
I wouldn't plan your retake date until we can figure out what went wrong. Once you have a good idea of what went wrong, then you'll know what you need to do to try to make it better—and that will help you to figure out how much time you need before you retake.
Can you give me some more details? What were your full scores for both official tests? (I want to know whether your score dropped about equally in the Q and V sections or whether one section was more responsible than the other.)
How did the tests feel? What felt the same and what felt different? How was your time management—did you have to rush to finish in either section? Did you leave any blank?
Or did you go too fast overall? Did you finish a section more than a few minutes early?
What did you do during the 4 weeks between the two exams? And what did you do in the 3-4 days before each exam?
Tell me anything else that you remember about either test—anything that felt different from one test to the other, or that felt different from practice tests—even if you don't think it's important.
Finally, you mentioned feeling some anxiety before the first test but not the second one. Sometime, test anxiety isn't obvious. Did you have any of the following symptoms (for either test date):
– Difficulty remembering the experience (don't remember the kinds of test details you would normally remember about a practice test; don't remember things about the testing center room that you would normally be able to remember after going into a new room or office space)
– Feeling like the large chunks of the text felt "foreign," like it was testing things that you'd never seen before; alternatively, feeling like the test only gave you things that are your big weaknesses (I once had a student tell me that her practice test had at least five combinatorics questions on it; when we checked, there was just one!).
– Feeling really distracted or having trouble concentrating—eg, you just read a paragraph and realize you have absolutely no idea what you just read and you have to read it again. Or you find yourself thinking about something other than the problem on screen right now—the last problem, or what your score might be, or even something unrelated, like whether you locked the door when you left your home that day
– The feeling that you were constantly agonizing between answers or other decisions—which method to use to answer a math problem, etc. (This often goes along with running out of time on the test.)
– The feeling that you just wanted the test to be over / didn't care as much as usual what answer you picked. (This often goes along with finishing the test or section really early.)
– Sweaty palms (or sweaty in general), upset stomach, dizziness, nausea