I'm scared! My uterus is measuring large, but no heartbeat?

If your worried have an ultrasound done at a pregnancy care net or something... Ten weeks is the very first week they expect to start hearing a heartbeat but it doesn't always happen that soon. The heart is still really tiny & the sound can be masked in your body by your own heartbeat! As far as measuring large goes... It may or may not indicate twins, but if it doesn't, watch your diet & exercise because it might be a precursor to gestational diabetes or sumthing?!