I know this is going to sound mad but for me, things improved when I stopped giving a shit and taking things personally. I've been treated badly by a fair few friends in the past but a while ago I decided enough was enough and that I was going to draw a line under it and not dwell on it any longer, accept that they were probably bitches and did it to as many people that they could get away with, and that I was going to be a lot more choosy with who I was friends with in future. I also decided to get close to fewer people, and to try to identify who was a casual acquaintance, and then if the casual acquaintance didn't act like a 'friend' I wouldn't be disappointed. And I've had a real think about what my boundaries are and what I'm prepared to tolerate. And the other thing is I've decided to keep people at arm's length more, and be very very choosy about who I will and won't confide in.
What I have also done is cut out anyone in my life, in a very subtle way, that I think has been a toxic influence. I had a couple of 'friends' from my DCs school that I felt were up and down with me, and often did/said quite toxic things so the first thing I did was pull back from them. I found having a think about my boundaries really made me make my boundaries firmer and made it clearer to me the kind of friends that I want.
Oddly since I've stopped giving a monkeys, I have more people inviting me out and wanting to be my 'friend' than I ever have done. I'm not quite sure what the turning point was for me not caring, it just sort of happened really. I'm never going to be one of those people that is in constant photos of nights out on FB, nor am I ever going to be a 'friend collector'. But that's because I choose not to be. I've realised I do actually really like my own company. I like seeing friends and acquaintances too, but not all the time, I like my own space too and time to spend with DH and the DCs. During the school holidays at Easter I met up with friends and their children once, but they were two lovely friends whose company I really enjoyed and the kids all got on well together. I'd sooner that than meeting up with different people every day and having to keep in touch with so many 'friends'. One FB friend of mine is always out with different people, tagging them on FB and posting photos, and it makes me feel exhausted the thought of having to keep up with, and socialise with, so many people!
I'd say these days I probably have round 4 or 5 people I'd say are true friends, in that they would be there for me if I needed any support or help. Three of these are online friends, and two are local. I don't see them all that often or keep in extremely frequent contact but I know they would be there for me if I needed them. I am close to my sister too.
I treat most other people as acquaintances really. I have nights out with them, or a coffee or whatever, but I don't expect anything from them. If I go out on a few nights out with them and then they arrange another night out without me it doesn't bother me, as I didn't rank them as a friend in the first place, so I have no expectations and just enjoy it when I do see them, if that makes sense. I make small talk at the school gates, and will go on mums nights out or chat at kids parties, but again everyone is very much at arm's length. I do still get people that treat me badly from time to time but I shrug it off and on reflection they are usually like it with loads of people anyway.