You dont lower your goals so that your ability can reach it.
You improve your ability so you reach your goals.
Compartmentalize. Make sure everything that you need to attend to before, during and immediately after the race is taken care of. family friends , relationships , work , bills , etc etc.
Manage your worries effectively. Committing to your race plan is the best way to do this. Now is not the time to make any major changes.
Focus on process not outcome goals.
"Outcome goals have their place, but the closer an athlete gets to a big event, the more outcome thoughts can create stress, anxiety, and distractions." Task goals, also known as process goals -- how to win -- are the best object of your attention during the last days before a big event.
Practice staying in "The Present." From here on in it's all about "The Now." Time to practice staying out of the past and not getting lost in the future. There are many techniques to do this, from focusing on your breathing, to setting the timer on your watch or cell phone to beep every so often to remind you to refocus on The Present (just in case you drifted off!). Remember, this is all about practice. No one (well maybe the Dali Lama) does this perfectly. So now is the time to get used to being present.
"Simplify. Simplify. Simplify." By the time you leave for your big event it's too late to to make any major changes in your life -- and probably too late to make many minor ones. So why stress out over something you can't control? Time to start cutting out anything that might be a distraction and keep it simple and focus on one thing at a time -- no multitasking.
While multi-tasking may feel like the right thing to do in today's complicated world, it is a recipe for mediocrity."