5 weeks no fetal pole

My last period was 1/1 and I believe I ovulated and conceived between 1/28 and 1/30 but not 100% sure as my cycle is not a regular 28 day cycle it has been closer to 35 days so I could have ovulated after the fact but the only time we had sex was between 1/27 and 1/30. At my confirmation appointment, the doctor was concerned that the sac is not as large as she’d like. There is definitely a sac there but no fetal pole and no heartbeat. It could be due to being too early but we are not sure and I am worried. The sonogram was measuring 5 weeks 3 days. I have another appointment in 2 weeks to see if there is any growth and a heart beat. Has this happened to anyone else? Trying to stay optimistic.