Half a life time ago, a colleague asked me if I was aware that if anything was suggested to me, I automatically said 'no' without even considering it?
I was horrified - not that they'd pointed it out, as I was very grateful they had - but because it was true.
I then discovered by monitoring what I thought and said that there was a split second while I drew breath to say something, and I began to use that pause to come up with a positive reply - 'yes, that's a good idea!' for instance.
I also learnt to 'reframe'what I was thinking i.e. not 'oh, that won't work' was turned into 'I wonder if we can make that work'.
It isn't easy to turn the dial from negative to positive, but if you really want to, I do believe a positive mental attitude is there for the cultivating. I'm now happier that I've ever been. I have very little in material terms but am rich in friends and family, have lots to interest me and I take huge delight in just being alive. If that brave colleague hadn't spoken up, goodness knows how I'd be feeling now . . .
My best wishes to you in your search for something better for yourself and others about you!