Please read -- Need help / suggestions

Hello everyone, I am about to take my test on Tuesday and am facing a problem. Two weeks prior, I took two 3rd party practice tests and scored 326(166Q,160V) in first test and 326(163V, 163Q) in second test. However, after a week break due to my exams, I am not able to score more than 156 (in both Quant and verbal sections).

I am losing marks in Text Completion and Sentence Equivalence which I earlier used to ace, and am getting better at Reading Comprehension section where I used to loose my marks before. AIso, I feel like I am not able to give my 100 percent attention and not able to stay vigilant throughout the exam, which is affecting both my quant and verbal scores.

I just wanted to ask if anyone has faced anything like this before and your suggestions on how to tackle this issue. Thanks in advance!