Went into a dark and cold cave in the Mountains?

The Mountains are called the Mountains of Madness?

Giant penguins?

Giant penguins that only eat human flesh?

Giant penguins worship Cthulhu and the other Elder Gods?

Starting to go crazy?

Killed your companions and/or family in the Mountains then returned to kill everyone else?

Suicide?

Conclusion: You got hit with the Crazies!

Symptoms of the crazies include: Madness, shouting at people for no reason, shouting at nothing, screaming at things that are in your head, hearing voices, hallucinations, hunger, homicidal tendencies, eating human flesh, murder, amnesia, dementia, schizophrenia, sickness, rape, and self-mutilation of any kind.

If you experience any of these symptoms then yeah you have the Crazies and possibly every disease known and unknown to man. Want the cure? There is not cure but start worshiping the Elder Gods immediately.