I'm having prolonged bleeding (spotting) since...

Treatment of prolonged period : 
the treatment depends on the cause so you should visit the Gynecologist and doing clinical examination and you can use Nonsteroidal anti inflammatory drugs which is the first line medical therapy for heavy and prolonged bleeding like Ibuprofen 600mg 2 times daily , or using Oral contraceptive pills as recommended by doctor in case of hormonal problems  , and may use Progestin which is the most frequently prescribed medicine for heavy and prolonged bleeding , anf if there is infection you can use Metronidazole 500mg 2 times daily for 10days 
Diagnosis : 
By taking full medical history and doing clinical examination and doing Complete blood count to detect infection and Coagulation factor studies , and Human chorionic gonadotropin (hCG) level , and Thyroid function tests and prolactin level and Hormone assays ( LH , FSH )  , and Pelvic ultrasonography
Causes : 

• Hormone imbalances
• Uterine or ovarian abnormalities
• Extreme exercise or dieting
• Stress
• some drugs
• Thyroid disorders 
• Sexually transmitted diseases
• Fibroids
• Endometriosis

Advice : 
you should visit the Gynecologist to get proper managment