So my lower stomach right above my pelvic bone has been hard for about 2 weeks now. I had my last period on the 9th of this month. My breast have become very tender and sore all the time. And I'm just exhausted all the time. Could this be a pregnancy? I took 2 test last week, both negative.

Around 2 weeks old, an embryo would be approximately 0.4mm in size. (http://www.visembryo.com/baby/7.html) That's about the width of your fingernail, so you probably wouldn't be able to feel it.

If I had to guess, it sounds like a poor diet. Most people do not eat right, especially when we're busy. Too much salt, fat, sugar, and/or caffeine can all cause breast tenderness, as they wreak havoc on the fluids and electrolytes in your body. (http://www.wikihealth.com/Breast_tenderness)

A diet high in these substances, especially caffeine and sugar, would also lead to fatigue because your body is not getting the healthy energy it needs. (http://www.health.com/health/article/0, 20409925,00.html)

Finally, a general tenderness sometimes accompanied with hardness in the abdomen near the intestines can be caused by gas, which can persist in the same general location.

If the problem persists, or if the pain becomes more intense, I'd suggest making an appointment with a doctor.