Me nd my gf had unprtcd sex on 11aug frm she was havng viral fever frm one week till yesterday nd her period was also came yestrdy bt her dt is 25th ?

Early period common.: She is 8 days early. It is very common to have hormone irregularity once in a while leading to irregular period. Viral infection can also play a role into this. I would not worry about this. At least she doesn't seem to be pregnant. I would strongly recommend to use some kind of protection if you continue to indulge into having sex unless she wants to get pregnant.