Late period & sex

So my period was late for about 23 days. I hadn’t had sex so there was no chance of pregnancy. I had sex last night for the first time in about 3 months so I had some blood spots right after but this morning the bleeding got heavier so I’m guessing it’s my period. What does this mean? I might sound dumb, but did it come bc I had sex? Did it have an effect on my period? I’m so curious 😅 if this has happened to anyone or if you might know what this means, please let me know! Thanks babes! ❤️