Am I overreacting? Boyfriend can go days without talking to me? Never asks to hang out?

My boyfriend and I are both 17. We go to the same school. See each other about 20 minutes each day, an additional 40 if our schedules line up. In the beginning of the relationship which was about three months ago, he used to text and call all the time. He would ask to see me all the time. Super affectionate in public/school. Always wanted to kiss, hug, hold hands. But now since beginning of December, he started to text less. He says he's going to call me, but always ends up taking naps when he says he's going to. He can go three to four days without talking to me. He's been "busy". He has medical and home issues so I haven't hung out with him after school since December 14th. I told him how I felt like I wasn't a priority anymore. He responded with how his life's been hectic. But ever since then he's been more distant. He rarely shows me affection in school or asks to me when our scheduled line up when he used to all the time. He never asks to hang out anymore. And recently, he told me how he hates when I bring up my feelings about the relationships and how I feel neglected because he's been busy lately, doesn't want to deal with it and it shatters his confidence. I haven't talked to him since Friday when he said this. He got me a promise ring for Christmas too and he says he loves me but I really don't know what's going on anymore. Is there something wrong with me? Did I do something wrong? What should I do? My mom suggests wait for him to come to me so I stopped texting him. It's been four days, how long should I wait? I honestly just want to text him and ask him to hang out but I don't want to seem needy... Help me please.
Updates
+1 y
He was on snapchat for the first time in a month... finally opened my snapchat from December 24th... is this a sign that he's actually thinking about me or is this just because he happened to open the app and decide to clear out the snaps he hasn't opened?
Am I overreacting? Boyfriend can go days without talking to me? Never asks to hang out?
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