Miscarrage and d&c 5 weeks ago. ovulated on 3rd week, hcg test were showing slight to neg. now getting slightly darker...?new pregnancy?

Possibly.: Pregnancy is unlikely so soon after a D & C, but it's possible. If your pregnancy test results were amibiguous, I suggest you wait a couple of days before repeating one. Then, test a specimen right after you get out of bed when the urine is most concentrated. In any case, given your medical issues and recent miscarriage, if you have any concerns, please get medical care. Best wishes!