The market is reacting today like if this is a big deal, short-term everything is. Long-term you can add this to one of the many uncertainties the market has shrugged off over time.
1. In the future, today's selloff will be an irrelevant data point in the SP500 chart just like 1987.
2. The longer your timeframe in the market the more irrelevant today's Brexit is. The two charts below tell you the whole story. The odds of SP500 being up in 5 years is 80%, the higher the "drop, the higher the odds of the SP500 being up. (I'm specifically talking about the SP500, not individual common stocks).
3. Pullbacks are buying opportunities in the SP500 for those who have time on their side, the bigger the correction, the better.
4. BREXIT will probably have little effect on your daily, weekly, monthly, usage of $AMZN and $FB.
5. Live to fight another day, be patient with your buys and always consistent with your long-term plan.