Hi, I'm 18 and currently on the pill.. I took my last pill on Thursday afternoon and I'm currently on my week break I have unprotected sexual intercourse on Saturday morning and he finished inside me.. Through out that day I had really tiny spot of blood when I went toilet and it's currently still happening I'm just wondering though could I possibly be pregnant ?

Pregnancy is entirely a possibility. No form, or combination thereof, of birth control is 100% effective. The symptoms you are experiencing would have nothing to do with pregnancy as it would be too soon, but possibly the beginning of your period.