So, in ten days I will have my period but my boobs are already killing me.

I did some cardio two days ago, and that was the moment when they started to really ache, my nipples are really sensible also.

Is it normal? Till now I didn't have this problem so soon, like before they would usually be really sensible before two-three days when my period came.

Also, I had sex with my bf last week when my period ended, an this week two times, when I was medium fertile. Without condom,but he came in my mouth and just one time on my back and it was.. all ok.

Should I be worried or it is normal?