Your last period was on Feb 9 th, so the expected date of next period for you is around march 9 th if you have a normal menstrual cycle of 30 days.
tenderness in the breast doesnot tells about pregnancy.
I will advice you to wait if your period restarts on the expected day on march 9th.
if there are no periods then you can go for home pregnancy test for urine. If it is negative you can repeat it after a week as it is sometimes negative in the early cases of pregnancy. Fconfirmation of pregnancy USG of the uterus & adnexa is the investigation of choice.
If you have still any doubt left, you can ask me.