I carry a .32 auto
If you are underpowered, than I am terribly underpowered. I carry a Kel Tec P32. That's a .32 auto, smaller and has less energy than the .380. Do I care? Yes. Can I do anything about it? No, because I have to dress light in the summer because of the heat, and I can't hide what I really want to carry--the .40 S&W.
A single shot with the .380 will, more times than not, bring down your attacker. Several shots will almost certainly kill your attacker. There are stories about crazed, drug-induced maniacs who get shot over and over again, only to keep on fighting the cops. That is rare, but that is the story that everybody hears. It is just not sensational when someone is killed with one shot.
The placement of your shots are all-important. If you are violently attacked by a homocidal maniac, and you have judged in the short time you have that shooting him him is your only means to avoid harm, then you have to keep your cool and be deliberate about where you place your shots. The best place to shoot an attacker who is carrying a contact weapon is in the pelvis.
A .380, even a .32 auto, will bring your attacker down if he is shot in the pelvis. It is mechanically impossible to remain standing with a bullet lodged in, or even near, the bladder--not to mention several bullets. If a kidney stone will bring the biggest man to his knees, imagine what a .380 bullet, or even a .32 auto, would do. A .38 Spl, .357 mag., 9X19, .40 S&W, and especially a .45ACP would be absolutely devastating to the pelvis. And your attacker may come to his senses if he sees you aiming at his groin area. He might think you are trying to shoot his wee wee off.
If the perp' has a gun, then I'm not going to be the one to tell you want to do.