Doubt

I am about 20 days into NC with my narcissistic ex-boyfriend of 2 years. I am struggling immensely with doubt. I am doubting that my ex was abusive and that he was narcissistic.
Some background. Our relationship was "perfect" for about 3 months. Things moved really quickly (said I love you within the first month). He was attentive and romantic. The perfect guy. Then I started to feel this distance. We went on less dates, and I didn't get the love notes anymore. We only spent time doing school work. I had to ask for him to take me out. He stopped asking what I wanted for dinner, we had what he wanted. He stopped asking what movie I wanted to watch we watched what he liked (unless I begged then he complained the whole time). Then we started arguing a lot. During arguments he would shut down and not talk, look at me or answer any questions. I admit to yelling and swearing. But it was never in a way to try and control him, it was out of hurt (not feeling like he cared) or feeling unheard. He told me he shut down because I yelled, but he did it even when I wasn't yelling, which makes me think maybe it was more about control as he didn't do it unless I was telling him I was upset about something. I sought professional help for my anger and asked him to do the same about his shutting-down. He never did and made excuse after excuse as to why. He did a lot of gaslighting "even if that was true" or "I think that's all in your head". He blamed and projected. My therapist seems to really think he shows at least narcissistic tendency, if not could be diagnosed with the full disorder. But I am having trouble holding onto that and find myself spiraling almost daily into thinking I am to blame. I am the reason he left.
When he left, it was after we had taken a nap in my bed. He was holding me and cuddling me. Then he broke up with me saying he wasn't happy with me anymore and didn't love me anymore. He hasn't spoken to me kindly since.
Anyone have advice or help? I almost feel like I am looking for someone to validate that what I went through was real.