Is my apartment safe or in danger ? should i worry?

Because you have all these health issues, your sense of perspective is more prone to focus on obsessing about every thing. You could ask for a tell tale to be fitted to your wall, this is two plates that will move if the crack does so aiding in the process of being able to say if the crack is getting bigger. having this will hopefully put your mind at ease about the crack anyway.You sound like you may benefit from Cognitive therapy (sort of distraction techniques) for your obsessions.