Scores dropping

I've been studying since October and my original test date was Feb. My scores weren't increasing after a lot of tutoring, and on individual sections I was scoring great but altogether it was completely different. I pushed back my feb test date to April because my scores were not what I needed them to be. Right before I took a two week break I scored the highest on a preptest (159), and when I came back from break I was right back to a 153 (my diagnostic score). My goal score is around a 163, but lately I haven't been able to break 154. I am used to scoring about 18-20 on each section individually, but altogether it seems to be a lot worse. I don't know what's happening to my scores but they just keep getting lower since I took the 2 week break from studying. I don't know what to do and the test is a month away, I want to at least get to 160 before the date. Help!