Vacation-eating on track till about 30 minute

I am on vacation with the family at the beach, and I've been doing great on plan -both diet and exercise----until about 30 minutes ago.  I had a half cup of dry cinnamon toast crunch cereal cause it was there.....what the heck.  Within a couple of minutes got soooo sick.  Another lesson learned the hard way.   I guess I am always gonna screw up.....back on track from this point on.  I will not eat that again.....once a puck inducer, always a puke inducer for me......you'd think I'd finally figure out to just stick to plan.