Does any one have any advice about how to move forward from the unwanted ending of a long term relationship when also dealing with anxiety?

My anxiety is mostly about my failures in life, people thinking I’m stupid/worthless or fear of making a fool of myself in some way or other, plus I get stressed and overwhelmed easily. However I never had anxiety about my wife who I was with for almost 10 years, in my mind we were perfect together, I trusted her unconditionally and felt completely at ease with her. I believe to me she was a stabilising force e.g yes maybe that person does think I’m an idiot but that matters less because this amazing person loves and respects me.

Well she left me, for me it came out of nowhere, she refused any possibility of working on the relationship in any way and moved on at the speed of light. The worst part is she hadn’t loved me for a year and a half and I couldn’t tell. At the time she used the “it’s not you it’s me” line but it’s since become apparent that that’s not exactly true.

My issues aside from the horrible breakup pain are:  

1. That I no longer have a way to convince myself that I have any value, I feel completely lost and alone – I have stuff going on in my head constantly, I can’t ground myself like I could before and just want to shut myself away in my flat.

2. I was completely oblivious to the fact that she didn’t love me for so long, it really makes me feel a huge worthless fool and as a result my anxiety feels so much worse. It’s not just about this relationship, it’s the fact that if I was so massively wrong about the person I thought I knew almost as well as myself then I can’t trust my instincts about literally anyone going forward.  

It’d be good to hear from people who’s been through similar. I’m in the UK and in a bad financial situation so I can’t afford to pay for therapy, I’m on an NHS waiting list for CBT but that does me little good now.