Extreme fatigue and nausea?

I don't know what's wrong with me. For an entire week I've been so tired, but for the past two days I've been exhausted to the point where I zone out like crazy and can't make it through the school day. I'm not PMSing and have been sleeping fine, I just feel so weak. My only other symptom is nausea, it got pretty bad last night but I never threw up and I can eat and everything, I'm just not hungry. I have no diarrhea and no actual stomach pain. Should I be worried at all? I'm a hypochondriac so I'm freaking out :(