The best way to tell if you are pregnant is to get tested. Also like the previous comment before me, breast tenderness can be from a period getting ready to start and I remember sometimes when I was on birth control I would get tenderness and be tired. It was one of the side effects of and then other times I would feel awesome. If you are concerned about pregnancy, take a home test or visit your doctor.
Not necessarily. Breast tenderness/swelling and tiredness can happen when your period is coming on.