Boyfriend issues

So, I feel like my boyfriend is using me for pictures to help him get off. He lives across the country, I'm 18 he's 20. He has the day off, he texted me this morning and we did out usual thing but then he just stopped talking to me as soon as I helped him get off and I haven't heard from him since. This isn't the first time he's done this either

also the only time he answers me is if it's about sex