What's wrong with me? I have nausea, headaches, dizziness, tiredness, sore back and drained all the time. I took a pregnancy test and it was negative.

Migraines. Sounds like you may at least have migraines. It is common to experience nausea, dizziness and tiredness with migraines. Have an evaluation by a neurologist to exclude other causes. There are several medications that are very effective in treating migraines.