shaky confidence 2 days before test

First, i want to thank everyone associated with GMATclub. I have not posted much at all, but have benefited tremendously from reading the advice and experience shared on this site.

So, I will be taking the GMAT on Monday morning (2 days away). I have been studying for about 2.5 months and about 2 weeks ago, i was starting to feel more confident about my potential. On my practice tests (GMAT prep and Manhattan) I was starting to consistently score in the high 600s (either 670 or 680). I spent a couple of evenings this past week reviewing some areas and took the other GMAT prep test on Thursday night. I could not believe it, but my score decreased dramatically from where it had been. It came back at 600.

Trying to make myself feel better and not loose all confidence so close to actual test day, i told myself that the score was a reflection of it being Thursday evening and my being tired from a stressful work week. However, the score still has a mental impact. I had a lighter day at work yesterday (Friday) and decided to take another practice test. This time i took a Manhattan CAT, and scored a 700! This is much more in line with where i had been scoring on previous tests (both gmat prep and manhattan) but was a solid 10 to 20 points higher.

I think i am probably being too neurotic about this... but does anyone have experience like this? I guess i'll know soon enough (monday morning) where i really am. my plan is to hit the books hard again today, do some light review tomorrow during the day and then work out and early bedtime.

Thanks again to all and any thoughts/suggestions are very appreciated.