Call the police from a neighbor's house or a public phone. At night, if you think you hear someone breaking in, leave safely if you can. Then call the police. If you can't leave, lock yourself in a room with a phone and call police. If an intruder is in your room, pretend you are asleep.
Guns are responsible for many accidental deaths in the home every year.
Think carefully before buying a gun. I you do own one, learn how to store it properly and use is safely . Join a neighborhood watch group. If one doesn't exist, you can start one with help from local law enforcement. Never leave a message on your answering machine that indicates you may be away from home.