Could The Drop In HCG Levels During Fourth Week Cause Miscarriage?

I am suppose to be 4 weeks and 5 days well we seen the sac and everything looked fine said it was too early to see the fetal pole my hcg was 26000 and has dropped to 19000 in a week. i am not sure if i am reading this right yet my hopes are up i have been trying for over a year.i have all the signs of pregnancy no cramping or spotting. you seem to be very enlightened on this topic so could you plz email and let me know if you think i have a valid pregnancy or if you think im going to have to have a dnc.i dont want to jump to the dnc if there is a glimmer of hope with what i have told you.