I noticed some blue veins on my breasts, they are sore too? I had protected sex on the last day of my period and I have a 31 day cycle could I be pregnant?

It's not very painful, my breasts are sore only on the outer parts. I had stretchy vaginal discharge for the last 2 days and it feels like I'm getting my period but I don't usually get the symptoms this early, I'm very worried.

I'm 16 years old, could this be hormonal changes?

Hello and welcome to EmpowHer,
Pregnancy is unlikely since you were not ovulating when you had intercourse. However, you should take a pregnancy test if you miss your period. If the pain in your breasts continue, you need to get a mammogram.
Faith