Went to the clinic yesterday, they ordered blood work to rule out pregnancy, if the bleeding continues and im not pregnant, what else could it be?

Vaginal bleeding. It could be due to many different things such as hypothyroidism, uterine fibroids, infectious causes including chlamydia and gonorrhea, menopause, endometrial or cervical cancer, etc. Or it could be dysfunctional uterine bleeding if other causes are ruled out. It would be helpful to know your age and medical history. Please talk to your doctor about what it could be.
Bleeding. If not pregnant, bleeding from insider the uterus could be from a hormonal imbalance, fibroids, polyps or a blood disorder. Get it checked out.