Boys🙄🙄🙄

Ok so I’ve been talking to this guy since December and he was so nice to me; we went on dates and we’ve had sex and we were texting loads and now all of a sudden he doesn’t seem interested anymore. He doesn’t reply to my texts and last night I asked him about it and he said “talk later, stuff going on rn” and later he posted a Snapchat story asking someone to text him without texting me back. I don’t know what to do, we were getting on so well. Any advice?