Hi doc. I use diane pills continue and my period...

Delayed period :
There are many causes for delayed period so you have at first to exclude pregnancy as it's the most common cause for delayed period as in your condition . If pregnancy tests were negative it could be the result of the side effects of the medications you used and your doctor will prescribe medication such as Cidolut nor twice daily for 3 weeks and follow up your condition .
What are the causes of menstrual cycle delay ?

• Pregnancy
• Stress
• polycystic ovary
• Hormonal disturbance
• Anxiety
• Thyroid dysfunction
• Hypothyroidism
• High prolactine

What are the sign and symptoms of Pregnancy ?
There are many signs and symptoms which can increase your suspicion of pregnancy , and these include :

• Delayed period .
• Nausea
• vomiting .
• Breast pain .
• Abdominal pain 
• low back pain .

What are the required tests ?

• Clinical assessment and Urine pregnancy test if your period was delayed .
• Blood Hcg level .
• US Abdomen and FSH , LH .
• TSH And Prolactine for thyroid disorders and Hyperprolactinemia .