Talk to Gynecologist on Early Pregnancy Issue

AOA it's my early pregnancy, according to LMP I'm 6 weeks pregnant. I'm having cramping n spotting since 2 days. today I had a scan and blood test. scan didn't show the gestational sac whereas serum beta HCG showed 26.39 value. what it could be? I want a second opinion whereas my Dr has suggested me to wait for 1 week n scan again.