Your Facebook Account was not "Hacked"
When someone is pretending to be you and sends messages to people on your friends list, your account was not "hacked." Rather, it's a minor case of identity theft. (They may not have your social security number or credit card information, but even by pretending to be you with simply a photo of you and your name, this still classifies as identity theft.) The term "hacking" generally describes a situation in which the functionality of software or hardware is altered or used in a way that contradicts its intended use set by the developer or manufacturer. That's not what's happening in this case.
Rather, they are pretending to be you (identity theft) in order to social engineer your friends and/or family. Social engineering involves psychologically manipulating individuals to divulge confidential information or perform certain actions. Their motive is usually financial gain, but it can also be espionage is political and industrial circumstances. Some people hack computers and networks; others hack people.
What can you do to protect yourself and others?
1. Edit your privacy settings: Set your posts, photos, your "about" section (which contains some PII, or personally identifiable information), and your friends list to be viewed by friends only, or only you depending on your preferences. This is critically important if you have children in a world where predators easily utilize the internet to exploit children. The more photos and posts you have set to public, the easier it is for someone to pretend to be you. (Also, don't put bumper stickers on your vehicles of where your children go to school. Predators pay attention to this.)
2. Know who your friends are. Not just who's on your friends list but also those who regularly or somewhat regularly message you. If you get a message from someone you haven't heard from in a long time, or a friend request from someone you know you're friends with, the likelihood is that this is a scammer pretending to be somebody you know so they can take advantage of your relationship with them and your friendliness to exploit you.
3. When you identify the fraudulent attempt, whether they're impersonating you or someone you know (or may not know in some cases), report and then block them immediately. Facebook is typically adept at eliminating those fake profiles. If you don't report them, you're just helping their chances of successfully exploiting someone else. If you're Christian, consider reporting them as loving your neighbor.
4. This is completely optional, but if you identify someone is a fraud and you find that you have free time on your hands or you're just bored, feel free to mess with them, because by wasting their time, they're not using the time they otherwise would have to manipulate someone's grandma into sending them her entire life's savings. Also, it's fun!
In our technological age where virtually everything is digital, it is paramount to protect your privacy and data online. Laxity in these will only set yourself up, and potentially your friends and/or family, to be exploited by cybercriminals. Social engineers are very good at what they do. If you say to yourself, "Oh that'll never happen to me," don't kid yourself. It can happen to you. There are two types of people who are most susceptible to these tactics: people who are wholly ignorant of these types of scammers, and people who have too much pride (pride goes before a fall and all that). So, if you haven't already, take the steps I provided above to protect yourself and others from such attempts. They won't completely prevent cybercriminals from such attempts, but they will significantly mitigate their attempts.