Twin 2 sac not very clear she said. HELP

On August 23 I transferred 2 embryos 5 day. I have been so nauseous and tired. I went for a scan today and it’s twins. Twin 1 is 6 weeks and Twin 2 5 weeks 5 days. Saw both flickering heartbeats. So happy. Going next week for second scan and hope to hear heartbeats. She said that Twin 2 the sac was not very clear. Did any every have this said to them before. Thanks Kathleen.