No, you shouldn't worry. At 10 weeks there is very little to show, and a first time mother will also take longer to show. The abdominal muscles are still tight because they have not been stretched before. I didn't show till 7 months with my daughter, and even at 39 weeks could still hide it. Very few believed I was so far along. Belly size does NOT indicate a miscarriage, nor does being large mean everything is well either. It is solely dependent on mother and THAT pregnancy alone.
Symptoms will usually start to subside around the 2nd trimester. At this time the placenta takes over and the hCG begins to level off and decline slightly. This leads to you not being so nauseated, fatigue lessening and you feeling overall better. You can of course always call your doctor and request an ultrasound be done for reassurance. Good luck!
i wish someone more knowledgeable than me would have commented! I am going through the same thing except I am only 5 weeks and lost everything that I had started feeling last week like tender breasts and nausea. My dr did a blood test today and is going to again next week to make sure my hcg is rising, he did say he wasn't super worried about it because I am not bleeding or cramping. Hopefully you don't have any of that going with it.