Condom came off

So me and my new partner of almost 7 months were having sex today, doggy style and he pulled out and said the condom came off inside of me. This has never happened to me before. He helped me get it out but my question is, could I have been exposed to diseases since it came off and he noticed immediately and put another one on? We continued after that but I just want to make sure. What are the chances of something being passed if he noticed immediately and pulled all the way out…