Struggling to feel happy or excited about new pregnancy

I lost my twin boys at 20 weeks in August, which was completely devastating. I am now pregnant with my rainbow, 8 weeks along. I went along to an early scan today to check on my everything and I was, of course, relieved to hear a heart beat and see the baby is measuring on track. But I just felt so sad that it wasn’t my boys that I was seeing on the scan that I cried immediately after. I miss them so much and would give anything to have them back. I really hope that I can look forward to meeting this baby at some point, but right now I just can’t. Does anyone else relate to this?