Not necessarily. Breast tenderness/swelling and tiredness can happen when your period is coming on.
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.