HCG levels at 6 weeks

Terran

I just went and got my blood drawn last Wednesday on may 26th and the results were 31,271 and then I went for my repeat on may 28th and my HCG was 39,445! Is this okay? Is it rising good enough? I went for an ultrasound on the 26th and we did not see anything on ultrasound at all! So just been worried