4 days late on period 2 tests negative sore breasts, sickness, headache, doctor won't do blood test. what's wrong?

Probably nothing: You can employ supportive measures (e.g. Tylenol (acetaminophen) for headaches, support bra for the sore breasts and avoidance of stimulation, etc...) for the time being. A urine pregnancy test can be repeated in 1 week. If the other, non-specific symptoms (e.g. headaches, sickness) continue, get with your PCP (primary care provider/Internist/Family Practitioner) for some blood work (CBC, CMP) and a work-up.

Likely nothing: You may wish to repeat the home pregnancy test in 3-4 days. Use first morning urine and follow the instructions carefully. Menstrual irregularities are not uncommon and anovulatory cycle is a common cause. If you miss more than two periods it would be time to see your doctor. Consult this site for more information on this topic. http://www.nichd.nih.gov/health/topics/menstruation/conditioninfo/Pages/causes.aspx