Bleeding after sex😁

chloe • 💙💛💚💜❤️
Help😔 Me and my bf had sex and when i went to the toilet about 30 minutes later there was no blood in my panties but there was lots of blood in the toilet and some on the tissue. The only thing is i am due for my period so i dont know if i should just count it as the start of my period. 
Could someone give me some advice please? Has this happened to you before? 
thanks x