Need advice please?

I think the guy I am talking to changed his number out of the blue like without telling me. I'm not 100% sure but he usually answers my text messages and stuff. And then recently it's just been on read. Is there any way to find out his new number or if he changed it if so how? Because he said I could talk to him about important stuff (I get stomach aches a lot and usually tell him this) also his birthday is soon and I wanted to wish him a happy birthday and adding to this I'm very confused and stuff like struggling to understand what I did wrong and what is going on.. I'm feeling very frustrated at the moment. Relationships are difficult for me because I have a learning disability ( and I've told him this like l've mentioned my disability before and how communication and understanding peoples cues are difficult for me ) so I don't understand really why he would change his number out of blue without even telling me first. I didn't get any signs from him that he wanted to be left alone or anything. any advice would be appreciated thanks
Need advice please?
Post Opinion