Help condom slipped

So I was having sex and then the condom slipped out and we didn't realize till a bit then he told me m, so we just put on a new condom on and just keep going when we where done and he left I found the first condom was still in me, he didn't cum in the first on but I'm still a bit unsure, I don't want to get pregnant as I'm only 17 so if someone can give me some advice I would really appreciate it 😊