hi Cleanglass,
you have been through a traumatic experience. feelings are still very raw. in a way, the world does seem like a darker place - no doubt you never imagined the complexity of the experience you have been through. i dont know that anyone among us did. it certainly made me fearful and disdainful of others - i sincerely questioned whether my own perceptions and decisions making processes werent a detriment to myself. thats a scary place to be. youre in the good company of people that understand what you are going through.
good news: everyone is not insane

. in fact, most people are not; far from it. on the other hand, you may be seeing that the world is complicated, and full of complex people. about 30% of people at a given time suffer from a form of mental illness (which may include anything from depression or anxiety to substance abuse). on top of that, everyone to some degree carries baggage, dysfunctional coping mechanisms, immaturity, etc.
its not necessarily the prettiest picture, but it hardly means that its impossible for you to live a happy life. in fact, you and you alone hold those keys.
it took me a few years past "getting over" the relationship to really see that and radically accept it. if the world has challenging people/personalities, and i was now aware of that, then it was up to me to adapt, or not; to self isolate and live in fear, or to trust with some inherent risk but incredible reward, while also maintaining my boundaries, recognizing that trust and intimacy develop slowly over time, and doing it all in a bit smarter, less reckless way than i had been.
to reiterate, i didnt come to that place over night. i had hurt to process, and so do you, and what you are experiencing is a natural result of that hurt you are processing.
more immediately: can you elaborate on the friends that you thought were good friends that now seem like hard work? do you have people close to you that love and support you?