Should I get a second opinion?

I went to the doctor when I was suppose to be 7 weeks pregnant to have a sonogram to confirm my pregnancy is in my uterus and not my tube. The scan confirmed I had a sac in my uterus, but the sac was measuring 5w4d.. Just under 2 weeks where I should have been. The doctor also couldnt see a fetal pole or yolk sac. So he took some blood to see what my hcg levels were and wanted me back in 5 days for a follow up sonogram. I came back and the sac was measuring 6 weeks exactly, but still couldnt see a fetal pole, yolk sac or heartbeat. He said my hcg levels were pretty high so he wanted to take some more blood and see if they have went up any. During the sonogram, which was done transvaginally he kept telling me my uterus was tilted very bad. The next day when he called me with my blood results he said my levels were still going up but he doesnt think this is going to be a successful pregnancy but doesnt reccommend a d&c just yet. Im so confused. I still have all of my pregnancy symptoms and have had no bleeding or anything. Its been 10 weeks since my LMP but since my sac is measuring 2 weeks behind it should be measuring 8 weeks this week. Should i get a second opinion from another doctor?? Wait it out and see what happens?? Has anyone had this happen before? Thanx