I'm 25 years old and healthy. I have always had a regular menstrual cycle, pretty much to the day. My last period was Wednesday, June 15th, meaning I was expecting my period Wednesday, July 13th. Tomorrow will be the 20th and I still have not had it, nor have I had any signs or symptoms of it. Typically before menstruating I get swollen breasts, lower abdominal discomfort, and bloating. There have been two times in my life that I have been late, but both of those times I exhibited the aforementioned symptoms while awaiting my period. This time, nothing - no signs at all. My partner and I have not been being very careful and I am not on birth control. I know we had unprotected sex while I was ovulating (given that I was ovulating at the time that I thought I was). I took a home pregnancy test this morning (first urine of the day) and it came back negative almost instantly. I followed all instructions for the test. The test was First Response and it was $25 for 2 tests. I have not changed patterns in exercising or diet and I have not been any more stressed than normal. I would like to say confidently that I am not pregnant, but it is unlike me to be late and I have never in my life skipped a period. Should I wait a few days and take the 2nd test, or schedule a doctor's appointment? Also, what are the odds that a HPT can be negative after being a week late?