Need opinions!

My friend was supposed to have a visit from AF on January 21 and she never showed she waited a week took a test negative... she waited another week still no sign of AF went to her dr and got blood work done and it came back negative 😞. She’s going back to her dr on the 8th of this month because AF still has not come! Is it possible she could still be pregnant?! I need some opinions and advice for her!