I think my ex is ghosting me

so my ex and I broke up back at the end of October. i don't think either of us wanted to, but he goes to military school and we hadn't seen each other for 4 months and probably wouldn't see each other for another 4- we were having (small) fights often and we were both just so insanely busy with college so the best decision was to end it. he told me that he wanted to stay close and still text/call, and I said I was fine with that but that I needed a little bit of time to process. he said he still had feelings for me and at first he was calling me 1-3x a week just for 10 or so min to check in, and we were still snapchatting all day. that continued for about a month, but recently it seems like he's pulling away. he leaves me on open on snapchat for hours and we went from snap chatting 15-20 times a day to once a day. these past couple of days I've had to double snap him to get a response. I sensed something was off and so I asked him if something was wrong and that I kind of felt like he didn't want to talk anymore, and he said that it wasn't that he didn't want to talk, just that we rarely have actual convos on snap so he figures he'll reply to me later. I've tried having actual convos but they just fizzle out and it honestly makes me feel like shit that he keeps leaving me on open so I don't want to keep trying. I don't know why he'd say it's not that he doesn't want to talk to me if it clearly seems like he doesn't want to? It seems like he's getting ready to break our streak and it stings. should I just let this go and stop trying? I really don't want to but I'm also not going to make myself look like a clown to keep in contact with someone who doesn't seem like they want to be in contact with me anymore ☹️ I really thought we'd stay close, this was his idea anyway