Pregnancy ultrasound

Ne

So I’m 5 weeks and 4 days pregnant.

I found out last Monday my HCG WAS 129z I went back Friday night and it was 638.8

Tuesday morning it was 1530. Is this normal? They also said they only saw a TINY sac, no yolk or fetal petal and that was at 5 weeks 2 days. Just some advice please, first time mom