Normal ranges for 5 weeks is 18 - 7340 , so i would not worry just yet, in early pregnancy your dates can be off, and HcG can rise slowly in some women even throughout pregnancy. Remember it's not the single number that counts, it is if it double in 48-72 hours
I know it is hard not to worry, i got a positve hpt just on 2nd Dec, and have had brown spotting since that day, and my first appointment is tommorow, so i know how hard it is not to worry.
Big hugs xx
Oh and this is the chart for 'usual' HcG levels
3 weeks LMP 5 – 50 mIU/ml
4 weeks LMP 5 – 426 mIU/ml
5 weeks LMP 18 – 7,340 mIU/ml
6 weeks LMP 1,080 – 56,500 mIU/ml
7-8 weeks LMP 7, 650 – 229,000 mIU/ml
9-12 weeks LMP 25,700 – 288,000 mIU/ml
13-16 weeks LMP 13,300 – 254,000 mIU/ml
17-24 weeks LMP 4,060 – 165,400 mIU/ml
25-40 weeks LMP 3,640 – 117,000 mIU/ml
Women who are not pregnant <5.0 mIU/ml
Women after menopause 9.5 mIU/ml
NB It is important to remember that these numbers are intended as a guideline only. They are not definitive and are just meant to give an indication of what can be an average hCG range. Every woman and her pregnancy are unique and what is considered normal for one may not be for another. (from source)