I had a miscarriage 5 weeks ago, d&c almost 3 weeks ago. my hcg level was 12 week and half ago. having pregnant symptoms again. pos hpt? could i be preg?

Probably not: Your body won't start cycling again (producing eggs to ovulate) until the quant HCG has fallen to zero, and the dropping to zero (from 12) probably took another week or so. The process of recruiting a new egg, and it maturing and being released would take likely tak a little longer than a week and a half to occur once the quant fell to zero.