Period 3 weeks late, not late in 2 years. cramping comes goes, even skips days. many egative preg tests at home. no sore breasts. what's going on?

Period "late": Although in one's mid-30's delays in ovulation are common, which will delay the onset of a period, symptoms of cramping may indicate a pregnancy outside the uterus, and the amount of pregnancy hormone produced may be below that necessary for a positive test with "home pregnancy testing". Obtain a serum HCG test, which is very accurate. See your gyn physician immediately if positive.

Hormonal imbalance: 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. If you do not wish to be pregnant, use contraception all the time. You may consider implanted contraceptive or an IUD. Consult this site. http://www.nichd.nih.gov/health/topics/menstruation/conditioninfo/Pages/causes.aspx

See your GYN: The best way to be sure is to see your OB/Gyn. The tests they use are much more accurate and they can also check for other possible causes. Being late is not necessarily a reason for concern, but if it is worrying you than that is reason enough to schedule an appointment :)