Thanks for the query.
You better consult gynecologist once, get examined and go for one ultrasound
Because your symptoms suggesting the possibility of ectopic pregnancy
Sometimes urine pregnancy test kits may not detect early pregnancy.
Don't worry this is a rare possibility, but better to rule out as early as possible.
For more details you can ask me through: http://www.healthcaremagic.com/doctors/dr-sree-gouri-sr/63429