5 weeks pregnant and bleeding for 5 days?

My dr keeps saying I will have a miscarriage, but my hcg levels are still increasing..I have been bleeding/spotting for 5 days now, ever since my dr examined my cervix...but the only time I see blood is if I wipe...nothing in my panties, and no clots. But the blood changes colors..sometimes it is brown and sometimes red.. Is it possible that this is normal and my body is just reacting strange? If it is a miscarriage then why is it lasting so long? Wouldn't I have only bled 1 day? And wouldn't I have had a gush of blood or clots??