Advice??

Alright so i want you guys to tell me what to do. so me and this guy have been talking for a while now and this week we hung out. well after we hung out he kept on messaging me and later on he said he wanted to see me again sometime next week and said it again like two more times in the conversation. but then all of a sudden he left me on read and hasn't talked to me since. it's been like 4 days. also i'm 18 and he's 21 and this is the first time i've been with an older guy. should i swallow my pride and message him or should i just give up? i really liked hanging out with him. and when he said he wanted to hang out i said me too