Negative Pregnancy Test Results With Symptoms

Patient: I have missed my period. Its only a few days late. I have been noticing some changes going on though. Im hungry often and pee frequently. I have tenderness in my nipples. My lower back is achy. I took a pregnancy test it came back negative. If im pregnant I know it could have only happened about 2 weeks ago. Is it too early? Or am I not pregnant?

Symptoms: Lower back pain, increased appetite, frequent urination, mild cramping, nipple tenderness, missed period