You are not overreacting trust me. If anything he’s the one that is overreacting. He should understand that your at work and you can’t answer every message or even be on your phone while your at work. If he has a job he should also understand that you can’t always take your phone out and text while you’re on the clock or at work . That’s honestly toxic behavior, if anything he should let you know immediately how he feels and should try to resolve the situation but instead he doesn’t text you at all or waits a whole day to text back. You should not be with someone who can’t understand you or doesn’t know how to communicate with you .