Hello Doctors! My Ex Boyfriend Was Playing Around With Me

Hello doctors! My ex boyfriend was playing around with me on Dec. 20th and put in the tip of his penis inside without a condom. Needless to say we aren't talking anymore. I know that sperm only survives in the vagina for up to 5 days and it has been at least a week since then. My period is now two days late but I am still having my normal early cramps. Could I be pregnant?