Help please! is depression/self harm "contagious"?

No, but....: Depression and/or self harm is not contagious. Does it affect those around you yes. But it doesn't cause others to be equally depressed or self-harming. If they are depressed and self-harming it can intensify their feelings and sense of responsibility for your well-being. I would advise going to a therapist to discuss this further.

Not infectious: Depression and self-harm are not contagious like an infectious illness. But if surrounded by depressed people who use self-harm to deal with pain, younger people might learn that this is the way to deal with life -- or might not realize that there are other ways to cope with disappointments, etc. Get some other viewpoints. Also, please consider seeing a psychologist or other therapist about this.