I think i missed my period? my cycles are average 37 last day i had my period was aug 31 and it's oct 15 i have taken hpt all neg am i pregnant?

Not pregnant, but...: Properly done, negative urine pregnancy tests means not pregnant, unless the pregnancy just began less than 2 weeks ago. Other causes of a late period include: excessive weight loss or weight gain, increased exercising, emotional stress, having an illness, traveling, medicines (especially birth control pills), hormonal disorders, etc… a visit to one’s ob-gyn doctor can help if one is worried.

Delayed periods: You are delayed about 5 weeks from your periods got by this time should be positive repeat it or have your md do it in lab if negative wait for total of 3 to 4 months and then have md look for other causes.