Hmmm this is just me Theorizing. So Pico suffering from ptsd and possibly self loathing as He constantly feels like the days are repeating, he try’s seeing a therapist for help and he gives him weed to help sooth his mind. It doesn’t help and he constantly stands by the ocean thinking about suicide. Nene being also traumatized, fears Pico for what he's become. Pico try’s to patch up there friendship again but Nene was still scared. In the end Pico finally jumps and now nene was filled with guilt knowing she could have helped.