Am I pregnant or HPT correct?

Patient: I have not gotten an actual period since August 4th. I started the NuvaRing as instructed that sunday. I took it out after 5-6 days and had unprotected sex August 23rd and 24th. On the 25th I had withdrawal bleeding for 5 days. Now I have not seen my period on Sept 4th. had sex Sept 5th until the 10th because we are trying to conceive. I have had sex many days after that as well. Still no sign of a period. According to babycenter with my period being on the 4th I would be 6 weeks pregnant and using the date of the 25th I would be able to test on the 22nd and get a positive test. Either way I am still testing NEGATIVE ­čÖü I started prenatals pills today, so i can increase my chances if i am not pregnant now….What could be wrong? Should I get a blood test or ultrasound done?

Symptoms: Nausea, tired, sore breast, cramping, back spasms