My period is 4 days late, i have all the pregnancy symptoms, including lower back pain, but all the home urine tests i've taken came back negative, i am so confused, please help, i really want to have a baby :?

Forget symptoms, none are indicative of pregnancy. Wait another few days and retest... a week to ten days after a missed period is the time to test.

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. http://www.nichd.nih.gov/health/topics/menstruation/conditioninfo/Pages/causes.aspx Get HPV vaccine.