Hcg levels

On the 18th my hcg levels we 32 today the 25th my hcg level was 580 they said I'm between 4-6weeks pregnant based on hcg levels... I thought they would have been much higher by now still glad to see they went up allot but just wanted my chicas thoughts on it so what do you think is it normal or should I be concerned my next appointment is april 5th I haven't had a ultrasound yet so maybe that's why I'm nervous guess I just need some reassurance everything is ok thanks chicas