The Up and Down Skill Level Pattern?

Friday, I again, was playing fairly decently, then got a match with this guy who I'm not sure I'd ever seen before.  He asked if I played for time or anything, I said nope, just fun.  Good thing too.  I won the first two racks, but then the hour of shit-horse play struck me in the face. and I lost the next 8 matches.  Then I won one and proceeded to miss, yet again, another relatively simple shot in the next rack.  I'm not sure I won another game.  He went to go play one-pocket with some other guys eventually, but the finally tally was something like 13-3.  It was mostly light-hearted and at one point he did mention that he knows I can shoot, i'm just off.  Which is true - it comes in waves.  Good for 2 hours, suck for 2 hours, good for 2 hours, suck for 2 hours.  I just hate it that it always seems to happen when I get a match.  It's my biggest reason for not signing up for the tournament in 2 days yet.  I suppose I should just to get the experience and maybe get some sort of ranking, but... I don't feel confident that I'd make it past the first round; and all that's all I want to do.  Not get eliminated the first game.

Anyway, friday night, xy and I went to the hall again and nearly closed it down.  The same pattern of start good, suck then end decent appeared.  I'm more able to identify what's happening now, but making the adjustment - and keeping it there is still quite difficult.  oh well.  it's all practice, right?  My accuracy is going up though.  on a decently spread table i'm averaging 4-6 balls now i think.  I have to get to my practice log to make sure.