Hi eden, I'm sorry you've been so let down
I'd say that we have to accept that occasionally unavoidable situations might come up whereas someone has to cancel through no fault of their own, but this seems to be more than occasionally and at times when you need that input/or to be able to trust that they will be there, right??
Do you think that you could explain how this is making you feel to your psychologist (when you manage to meet!!) then maybe if it's going to be a matter of prioritising appointments at any time he might prioritize being there for your appointments more highly and, at other times, at least make sure you're contacted as far ahead of time as possible if they need to be cancelled.
But if that's not working and you're regularly missing appointments/being cancelled on, then I'd say it was definitely time to ask for another psychologist.
Afterall you need to know that you can trust them, that what you're going through is important to them, and you need to feel secure in the "relationship", right??

And now.......maybe write down (if you haven't already!!) all the things you wanted to/want to say to them for next time around. Then deep breaths, remember no-one is worth causing you to feel this badly. No-one!!! So try not to give them that power over you, hey?? They don't deserve it!!!
Just try to keep the focus on you, and on making it through........so any coping skills you have that might help just a bit.......even just a bit is going to be good.
And if there's anyone else you can contact for now........??? E.g. maybe your doctor could help with mediation???

But the everybody hating you bit........It can be easy to feel rejected, abandoned, dismissed by others when you're struggling but that isn't always going to portray their true feelings towards you. Maybe talk to them about the way they're making you feel and give them a chance to give you their perspectives/reasons for........ how they really feel???
But just know, you're NOT hated on here!!!

Alison