How could I be so stupid

I tried reaching out to a guy I was talking to and really into and saw he disappeared this morning so I had a quick check and turned out he blocked me on Instagram. The reason? He had posted today that he had an amazing valentines with his girlfriend. Funny that cause I had a bad feeling and decided to stop talking on guess when? The morning of valentines day. I had absolutely no idea he had a gf. He made me think I was the only girl he was talking to, we used to talk on the phone constantly, had loads of amazing deep conversations and it all meant nothing. I can't believe I was so so stupid to believe him. How could I not have known he had a girl? My trust is absolutely shattered. I sent him a message saying how he was such a good actor and liar, also saying how can he sleep at night knowing he does this to people, before blocking his number. How am I supposed to move past this? I have absolutely no trust anymore. I should've seen the red flag when he told me he was in the army but he kept proclaiming that he "wasn't like that" and "hated that label" but he just proved me right. I feel sick and cold and I'm shaking, idk what to do atm