You have to watch this video in its entirety and as uncomfortable as you feel this poor soul was feeling much, much worse! Fortunately, this one got rescued but how many others are in the oceans right now facing a long agonising death.
As conscientious as you are in ensuring that you dispose of the straw responsibly, inevitably some of it will reach the ocean. Most straws are made from polypropylene and it can take up to 200 years to decompose. Unfortunately, sea turtles and other marine life mistake the straws for food and most likely this creature ate it, was unable to digest it and tried to regurtitate it out through her nostrils.
Can one person make a difference? Yes, for the person that threw that particular straw away, it made a difference to that sea turtle! And you can make a difference by choosing not to use a plastic straw. If you are in a restaurant and you are served drinks in a plastic straw, reject it and tell the staff that you do not wish to use a plastic straw. If they do not offer a suitable alternative, try sipping your drinks instead!