Early preg symptoms

I have heard about breast tenderness early in pregnancy..My periods are sue in a week but I think I had implantation bleeding...and only one of my breasts is very sore...Is this normal?

Yes, the symptoms of the early pregnancy are surely all that you mentioned, but you should wait a few days more and see if you will get your period, if it is late, you then start thinking that you are pregnant. When did you get the implantation bleeding? If it happened like 10 days ago, it could be due to your ovulation which usually happens in the middle of your cycle.
Have you experienced fatigue or vomiting? These could also indicate pregnancy.
Tender swollen breasts are surely the early symptom. While tender breasts are a symptom of an impending menstrual cycle, enlarged breasts are not. Sore and swollen breasts with a tingling sensation can be an early indicator of pregnancy, so you have to define what kind of soreness this is.
However, I wish you all the best and if it happens that you are pregnant I hope you will make the right decision!