Recovering from brain fog post manipulation

I had recently cut off a FWB due to constant manipulation and gaslighting. We were friends initially, he seemed perfectly normal, empathetic and also accountable for any mistakes he made. I thought he was a good person, I felt comfortable, trusted and we ended up sexting a few times. And stuff started going downhill gradually. He would constantly take a moral high ground no matter how wrong he is and constantly shame me & put me down to put all the blame on me. Initially, I fought this a lot even decided to leave at earlier stages. Whenever I got ready to leave, he will change his strategy and start playing the nice guy again. This process repeated a few times, sometimes I started questioned myself if I was too sensitive and if my reality and perception was wrong. But there were too much lies and inconsistencies. Thankfully, I left in a couple of months. I have blocked him everywhere a couple of days back.

I know this isn't my fault. But as the brain fog is clearing and I am seeing for what he actually was? I am starting to blame myself a lot. I am questioning what was real? what was not? Because there was red flags everywhere, I keep asking myself how I let this happen? How did I let this happen? I am shaming myself constantly. I have shut myself off and just sitting by myself in this pain, regret and hurt. I don't know how to recover from this.