Random Bleeding??

The last day of my period was the 15th of May. Today the 25th I randomly had a blood clot it was very tiny and stretchy and it was like I started my period again. My periods are usually on time and if they are on time my period wasn’t supposed to come until June 8th. Well now it hasnt even gone anywhere and i have no more blood. It was like a one time thing. Ive never had that before. My boyfriend and i had sex last night. Idk if thats because of that. But ive never just randomly spotted like a lot and then nothing. I have no cramps or pain. So confusing.